Wife and I have been wanting to visit, possibly 4 of us with another couple.
So yes, I can start researching and get info, but I'd like to get a feel from you guys first (I love ATOT's anecdotes and personal experience)
1. Yosemite is HUGE, so do you just camp into the woods? There must be a 'main entrance' of sort similar to South Rim of Grand Canyon to do general mainsteram hiking and stuff?
Most people (more on this later) stay in the valley. Lodging fills up very quickly and you really need to get in on it the instant reservations are made available. There is a lodge as well. There is Camp 4 (the climbers' hangout) which doesn't take reservations, but you'll have to get in line super early in the morning if you hope to get a spot. There are also places to stay just outside the park, but that means a hefty trek into the valley to get there.
There is backcountry camping. You will need a permit (which can be reserved), but can otherwise camp wherever you hike as long as it's in the wilderness areas. If you're a backpacking type, it's a good way to escape the crowds a little bit at least.
2. Sorry, let me back up, when is the best time to go? For how long? Where to stay?
Depends on what you want to do. If you want to see the waterfalls, early June is probably your best bet. If you want to hike the backcountry, probably July through September. If you want a change of pace and don't mind the cold/limited availability, the winter is the one time that the park will not feel crowded. If you go in July or later in the season, spend some time up by the Tuolumne Meadows, which will be less crowded and provide a very different, but no less beautiful, landscape.
How long depends on what you do. If you're staying just in the valley, you can probably see everything you want in a week or two. If you're going into the backcountry, you could easily spend a month or more and leave feeling like you didn't hit everything.
3. I heard they only have VERY limited cabins for rent and they fill up fast? Are there designated campgrounds as well?
See above.
4. You just generally hike there most of the time I presume? Any other activities for casual crowd?
Let's start with these. 🙂
There are some awesome Sequoia groves that are a little ways from the valley and generally less crowded. If you've never seen a redwood, it's an awesome experience.
There's a bus tour that goes up to Glacier Point. If you're not a strong hiker, I recommend taking the bus up to there and then walking down to the valley. It's a fantastic trip, some of it will actually feel quiet, and it's less strenuous than walking up out of the valley.
Yosemite is beautiful, but unfortunately everyone knows it. It's super crowded during the times you most want to be there. It's definitely worth going to see, but personally I much prefer King's Canyon for a Sierra Mountains experience. King's is far less crowded and the valley is just as deep. The only difference is you don't have the Half Dome and El Cap.
If your goal is to just see mountains, I'd go with Glacier. It's my favorite US park I've been to so far. The landscapes there, IMO are even more impressive than Yosemite.
Both of these suggestions are a bit more rugged than Yosemite, though. A casual alternative would be the Tetons, which you can also easily combine with a trip to Yellowstone. There are a lot of guided horse tours in both parks that make them really accessible.
