My family stayed in Redwoods and Simmons cottage for three nights in June. Simmons cottage has a good location next to the reception where you have laundry possibilities (Though only during the opening hours till 5pm...and usually most people are in the Valley or hiking at that hour. You need to see some effort to do your laundry which was really frustrating while spending only 3 days in Yosemite).
While being there we were hit by a heat wave and the temperature reached even 105-115F. Simmons cottage doesn't have air conditioning which meant that our nights were difficult for the kids and adults. The Simmons cottage is pretty dark, but there was enough room for our 5 person family. The kitchen has good equipment, but the dinner service is very limited, e.g. there are not enough glasses and flatware for breakfast and dinner - you have to do the dishes in between. The TV didn't function at all but we didn't really need it either.
Redwoods cottage camp/area is quite dreary and worn-out for Scandinavians. We do have same kinds of (purposely) primitive cottages, but the surroundings are usually more maintained and beautiful. For the price of this cottage we expected much better quality. In Scandinavia you would get a luxury holiday home for that price. Simmons is far from luxury in our opinion. On the other hand it was an interesting opportunity to see how the Americans design their holiday homes. Most cottages are probably from the 50's/60's.
Wawona is located nicely half way to the Valley so you avoid the car lines entering the park in the morning. We did also enjoy Wawona and the nearby sightseeing, e.g. the water fall and the river. If you stay here, I recommend visiting The Big Tree Lodge which is a beautiful Victorian house - just like from the movies. But it is fully booked in June, you need to be early bird to get a room. But you can use their pool (for $5 per person) and Saturdays they have BBQ outside (which was not worth the money, the food quality was worse than our school food), but it was nice event with some live music. The golf course is pathetic during the dry summer months. So don't count on that if you are a golfer. We also went to Shadow of the Giants close to Oakhurst (Mariposa sequoia tree park was closed) and Bass lake which are nice places to visit as well.
The main room was spacious and had great natural light, the kitchen was well appointed (the knives were actually sharpened!), and sleeping accommodations were simple yet comfortable. When it cooled down at night the central heat was nice to have. Perhaps our favorite feature was the large deck mottled with tree shade which made for a nice place to relax after spending the day exploring the valley floor. The general store, a short walk down the road, was great for picking up small necessities. My only knock is that the bathrooms were a tad small for larger folk. Otherwise we (two couples and a baby) had a fantastic time. Highly recommended.