Thoseare some great photos! Wow!
What's good about the Wonderland Trail? When the weather is cooperative, hiking the Wonderland ranks as a sublime experience. I agree that while not “true wilderness” it is nonetheless beautiful and is ideal for someone who wants a physical challenge without a tremendous amount of logistics.
I would categorize as a positive the controlled, permitted campsites along the Wonderland. Well, maybe not so good for those pursuing a solitary wilderness experience but good for the park itself. The mountain would be loved to death otherwise. The entire rationale for permitted campsites dates back to the era when you could camp anywhere. The results were none-too-pleasing. The meadows were overrun by throngs of backpackers and day hikers who were destroying the fragile habitat of the mountain. Mystic Lake is a prime example of an area that has really rebounded since they made this change.
The fact it is a loop makes it considerably easier to accomplish without a lot of additional logistics. One of the distinct advantages of the park is that you can cache your food at several locations along the trail. At most, you only have to carry three, maybe four days of food at most (depending upon your speed).
The NPS keep a percentage of sites along the Wonderland open for walk-ins, but if you want to have a more manageable schedule that allows you to pick where you want to camp, you must apply for a permit. I can’t emphasize this enough, this trail is quite popular. Information can be found here:
And here for the permit application itself
As to the number of people, Mt. Rainier is a destination National Park. It's proximity to Seattle makes it a day trip for many. Throngs of tourists visit. Plus, if you come in late July/August, you are at the height of the season, especially on a weekend. The season is short here - the Wonderland doesn't really open up until mid June at the earliest and this year there was quite a bit of snow on the trail through July. You have to deal with this. If you want to avoid crowds, plan your hike to avoid weekends spent in proximity to Sunrise, Paradise, Longmire, Summerland and Box Canyon. These areas are all popular.
Places I would definitely recommend camping:
Summerland - Get there early for choice camp sites. If you go back a ways into the campground, there are sites with especially nice views.
Indian Bar - If the weather is good, the hike between Summerland and Indian Bar is to be savored – a short day but one that demand you to take your time, scramble up to view points and enjoy the vistas. The group shelter here is excellent if you can get it reserved. If you take a regular site, I’d recommend avoiding staying near the river. By taking a spot high above the river and near the privy, you will be much warmer. The cold air from the mountain sinks into the valley, and combined with the river, make it wet and chilly.
Dick's Creek - A nice view plus breaks up a long climb to Mystic Lake. Although the campground at Mystic Lake isn’t terribly exciting (it’s in the woods), spending the evening by the lake and watching the sun set make Mystic Lake also a good selection.
Klapatche Park is a personal favorite – lovely campground on the west side. The west side is often referred to as the “wild side” of Mt. Rainier.
I would also recommend the Spray Park alternative. It’s quite scenic and a vast improvement over the traditional route. Camping at Mowich Lake is one place I’d avoid. Eagle’s Roost camp ground, which is in the trees on the way to Spray Park, is a better choice.
Finally, be advised that the Carbon River entrance completely changed several years ago. Flooding in 2006 wiped out the road that once traveled to the Ipsut Creek Campground. They converted the road into a rather wide trail, and it is five miles or so just to get to the Ipsuit Creek Campground from the ranger station. If you have an older book on Mt. Rainier, it might not reflect this status change.
What’s not so good? Well, when the weather turns, it can be very, very wet. Epic wet. And unfortunately, if it is quite wet, you can’t really see much of the mountain as you will spend a fair amount of time walking in the clouds. Keep in mind that August and September are generally the “dry” months in Washington. But it can rain, snow and get downright chilly. The mountain makes its own weather!
Other recommendations: If you choose to go slow or are with someone who loves the creature comforts, you might consider scheduling a night at the lodge at the Paradise Inn or an the National Park Inn at Longmire. The Paradise Inn is a bit of a climb off the traditional Wonderland Trail route (but can be incorporated as part of it without an issue). There is a small store at Longmire where you can buy beer and snacks. Although drinking too much and then immediately climbing toward Indian Henry’s Hunting ground is, from experience, not advised.