As I get older... lots older than 42, thank you... I tend to go solo because I'm a solitary sort and prefer not to deal with social situations except when I choose. And I prefer to set my own pace and trail time. Sound familiar?
A) Obviously, solo lets you go as far or as fast - or as slowly - as you like. Sounds like you already travel solo.
B) Solo on trails in the Sierra's? Dunno, not my line of country, but if you are on a trail, sit down and see how many folks pass you in an hour. There are not many places so isolated that you won't see at least one party per day.
C1) My significant other (when she isn't with me) and aged mom like for me to carry a cell phone. The understanding is that sometimes I will be out of service range and batteries don't last forever. No contact is not reason for concern. Sometimes the contact schedule is daily, sometimes weekly, depending on where I am. Whatever, it makes them feel better.
C2) Convince your wife that you won't show up unannounced, and C3)make sure she knows the life insurance is paid up. If that helps, maybe you need to spend lots more time on the trail or lots less, depending.... Or, as I told my mom once (C4) I always carry ID so they know where to send the body. OK, maybe not for you.
General thoughts? For me, it's the best way to travel. I can goof off or bust butt according to how I feel that day. I can bore myself with my conversation or not. It is more challenging and potentially a little dangerous, so I stay more aware, and I like that. (Whether it is more dangerous to travel alone is open to debate because each partner tends to rely on the other, and when everyone is responsible, no one is responsible. Also testosterone judgement is exacerbated in proportion to group size and leads to bad decisions.) I like feeling self-sufficient and self-contained. You have to think of everything, and that awareness becomes a background for the experience and heightens it.
And I like coming home.
AS to safety, Frick and others have covered the practical stuff such as first aid training - all good advice. One more thing on that. Get your family doc to prescribe or give you some serious pain killers - Darvoset, Roxicet, Oxicontin... some opiate way heavier than Vicodin. If you are seriously injured, heavy duty pain management will keep you from going into shock and will let you function well enough to take care of yourself. Tell your doc to imagine having to wrangle shelter, food and water for a day or two with a broken femur. If he doesn't understand that, get another doc. Good drugs are one secret to surviving serious injury. The other is experience with being seriously injured, but that don't come in a bottle. When taking painkiller in tablet form immediately after an injury, the way to get quick relief so you can deal with the injury is to chew 1/2 the dose and take it and the rest of the dose (intact tablet) with lots of water. The chewed tablet will hit you really fast. Otherwise you will wait 20 minutes for relief. And the first 20 minutes can be critical for avoiding shock - the greatest danger in these situations.