Sounds like you have most of it figured out for yourself already. So here are some random thoughts and musings on living a good life.
Each of us needs to live a good life, based on our own definition. Will your "ultralight" life be totally satisfying? You don't need material things to survive, but some things are what separate us humans from the animal world. Humans should live, not survive. Art, literature, and music are particularly important. Quality time with family is another. So you need to budget money for these. You can get some of this from libraries, matinees for plays and an occasional movie. Kindle edition of books are pretty cheap. It is amazing how cheap you can buy used books on Amazon. I just purchased 4 hardbound books this week and they were all under $10 each including tax and shipping! Expose your kids to as much of this as possible.
IMO, it is foolish to wait to live the "good life" until you retire, and you have figured that out already. You must live it starting today, with a plan to provide for your retirement and any emergencies.
I have been collecting postage stamps since I was about 10 years old or so. It does not need to be an expensive hobby, but the time spent learning about the history of each stamp in my collection has been a wonderful journey in itself. When I was younger, I also bought record albums, but was very selective as to what. Many, many hours of enjoyment since I was very young and it continues everyday of my life. I rarely purchase new music these days, because I enjoy what I have and it covers a wide genre of music. You must continue to grow your mind every single day. My hobbies have allowed me to do this since I was a kid. TV is not a necessity, but one should have a means to know what is happening in our world and wisely participate in our political system. It gives us a voice in our future, and ultimately in our quality of life. Many, many years ago I purchased a used set of "The Great Books of the Western World" and they have been my main reading material for the the past 30 years or so. Because I have always enjoyed reading, it was something my kids saw as normal and they became voracious readers too; and this is the basic building block to a good education. Both did well in school because of it. TV was not watched that often because all of us were too busy living a good life. Although there were video games and such, I did not allow them to own any at all.
My wife and I enjoy movies, but rarely go to see a movie; maybe once every couple of years. But for us, $7.99 a month for Netflix is a bargain and we watch maybe one or two Netflix movies a week. We also have cable for the movies and Internet. Movies are art... well some of it is. We still read a lot. Last week I re-read 3 of Colin Fletcher's books. This week I am re-reading 3 Edward Abbey books. And great books can pop up if one pays attention. Last year Bob Gross mentioned a movie called "And I Alone Survived." I bought a hard copy book on Amazon for $1.99, enjoyed the work and my wife is reading it now.
I started taking my kids camping when they were each 6 months old. We tent camped. My wife did not care for tent camping that much. So eventually we saved our money and purchased a small new tent trailer for $3,500 cash. That was in 1992, and the kids were 5 and 7 years old. This was one of the best investments I ever made, and not "ultralight." Everyone in the family loved to go camping with the pop-up. We went every year for a two week vacation in the Sierras. We went camping many weekends too. No electronic stuff went with us. Books were allowed. We are not a jigsaw puzzle family, but each vacation I would buy a puzzle themed to where we went. After we put the puzzle together, I framed it. We spent every day together as a family on vacation, spending hours fishing, hiking, swimming, bike riding, or just sitting around the campsite talking. The kids especially liked the trips to June Lake when we rented a small boat for a week. There was personal time each day and everyone would read the books they brought.
I often hear parents complain that their kids (especially teenagers) get bored easily and hate to go camping.
Both kids were involved in some sort of after school activity of their choosing, and we participated in every one, every day. My daughter tried sports at first then eventually gravitated to dance. My son always participated in sports. But theater or music are good avenues.
During this time, my backpacking was reduced. Weekends here and there, and one trip every year between Christmas and New Years. And some multi-day trips during the year. I was always willing to work a lot of hours in exchange for a little more time off. To me, a 60 hour work week is normal and easy. If you try hard enough, you will be surprised how many little day hikes you can squeeze in too.
Now lets talk about your job. Less and less satisfaction means you are not living a good life for large chunk of your life. I would change that immediately. The "how" is the difficulty. I have only had one job I hated. It was a 2nd job and I got out of that mess pronto. Some jobs seemed horrible to others, but I found ways to make them challenging and rewarding. Even when I worked pumping gas, I challenged myself to learn more about the business and that made everyday fun. You have to live ALL of your life with passion. Work is important, because we are wired to be productive. Our ancient ancestors died if they were not productive. I love to work, and love to enjoy my time off... every second of both.
Real Estate. I have owned property ever since I was a young man. All have resulted in additional income, far exceeding all the money invested and more money than I could have saved. My current house has fallen in value by over 50% the past few years, but I don't care because we plan on living here until we die, so market value means nothing. To me the ability to own property and even profit from it is one of man's greatest ideas and the concept of property is central to my philosophy. It is more than just property. But that is my opinion, and many would disagree.
Cars. We always buy new ones. But my vehicle is 9 years old and my wife's is 13 years old. When each dies, we will replace it with a new one. Pay cash of course.
Money. This is job one. Without producing and controlling it, you cannot live a good life. Money is only an exchange mechanism for the fruit of your labor, mind, or investment of the surplus. This is the easy part once you have a plan. Some would disagree, but if you have a 401K at work, contribute the maximum possible because income taxes are deferred and the tax money saved is more than you could earn by investing the money somewhere else in most instances -- and if your employer contributes -- even better. After you put away your emergency money, quit saving and investing (except 401K) until you pay off every debt. Pay off the highest interest ones off first with as much as you can afford each month, and make the minimum payment on the rest. As one is paid, concentrate on the next one with the highest interest rate. Once the debts are paid you will have a larger chunk of money to put away each month in your investments and you will have minimized the blood sucking interest quickly. Quicken Deluxe is a good tool to manage your finances and has a budget component to help you prioritize debt reduction. I have been using Quicken since the late 80's starting it on an Apple II. I have been using it on a MS/DOS or Windows platform since 1992 and have all historical data from that year forward. It has been my financial planning tool all these years.
College. This is a personal matter, but it is my belief that kids should pay for part of it. Let them know that now. Kids need to have "skin in the game." My kids paid for 1/2 of their college education, and they saved their own money as children (most money received as gifts went into the bank and they got to spend a small portion), and both worked through college. It took each of them 5 years to graduate. It is probably cheaper to get an education in California's public system, but we pay for it with higher taxes to live here, so in my mind it is somewhat of a balance.
Retirement. Since my wife and I put the maximum allowed into our 401K each year, plus we save and invest other money, and my wife has a employee stock purchase plan we do well. In the past 10 years alone we have put nearly $400,000 into the 401K's (we get to add and additional 5% because we are over 50). You are young, if you and your wife put the max in until you retire, you will be millionaires... but you have to love what you do!! We want our excess money to work for us. But we really live simply with few luxuries. We don't go out much even though we can easily afford it. We would rather spend the time at home together or go camping. I could retire today if I wanted to, but I enjoy my job too much (see my comments on working earlier). I probably will work another 4 or 5 years. If it continues to be fun, I might work until they fire me, or I get senile, or I die. Time will tell. The day I no longer enjoy working is the day I will quit. If income taxes get too high, then I will quit when that happens. I only want to work for myself, not others.
I am in my 60's now, but I would have regretted a minimal life without the movies, plays, concerts, literature, hobbies, camping, backpacking, hiking, motorcycle touring, museums, telescopes, county and state fairs, ghost towns, expositions, aquariums, zoos, music, fishing, stamp collecting, participating in many activities with my kids, dogs, work, art, etc. It would have not been a good life. It sounds like we are doing well, and we are; but for most of my first 30 years working, I worked mostly in gas stations, owned businesses at the same time, and went to college to get my degree. All of it was fun and rewarding. And I found plenty of time to enjoy the good life with my family and myself.
As I said earlier, we really live a fairly simple life. We do not entertain and rarely go to parties or social gatherings. But we do enjoy some luxuries. I would like to share a couple art pieces I purchased as Christmas gifts for my wife last year. The first was for me too, because I enjoy looking at it everyday sometimes for an hour at a time. No one has seen these except for us, because they are for our own personal pleasure. The second one took me nearly two years to find, and my wife especially enjoys it. Some would say it is extravagant consumerism, I say it is what makes us human and different from the rest of the animal world. Both pieces make the good life even better each day. Just remember, getting 100% out of debt is the only way one can truly live a good life, at least in my opinion. Anyway, a lot of rambling about a lot of things. Each of the things I have shared are components of my 60 years on this planet, and I have enjoyed every single day of it, and not a single day has been boring. If I die today, I will have no regrets at all -- it has been a great ride so far and I hope to continue the wonderful journey for many more years.
Good luck on your plan.