A lot of the camping in Yosemite is in so called "tent cabins". These are semi-permanent structures with a raised wooden floor and a sort of old fashioned tarp tent. IIRC, the bedding is a cot with wool blankets, which is very handy if you camp in the spring.
There are a couple of reasons for this kind of setup - some of them are good, some are questionable. When Yosemite flooded out a few years ago, it pretty much made the park floor unusable. In the interest of managing the over use of the park, they sort of bunched all of the camping into specific areas, and the raise platform tents fit into the reduced wear on the park concept. The downside, is that you are reasonably close to your neighbors.
Once you get there, Yosemite is nice to visit, and I wish we went there more often. Getting there is kind of a PITA IMHO, as no attempt has been made whatsoever to make this a family friendly road. A strategically placed bridge would cut the long and winding road time by 80%, but perhaps this is too progressive for such an area.
There is food sold in the park, but I suggest bringing some of your own also that does not need to be cooked. The restaraunt is open for meals, but at least when we went, not other times. If you are out hiking and return with a hungry family at "non meal times", you are limited to potato chips.
There most definitely are black bears in the park. The park provides food lockers for your stuff and make sure to use it. Even an empty food bag will attract them to your car at night, and they are just amazingly strong.
