M.D.
I can't recommend a specific RV park, but you might narrow it down by deciding which side of the park you want to camp on, which will change depending on what you plan to see while you are there. There are a number of entrances to the park, and each are convenient to different things. Here is a nice link:http://www.myyosemitepark.com/which-yosemite-entrance/
If you want to spend a lot of time in Yosemite Valley, which is the hub of activity, then Arch Rock entrance is shortest drive from outside the park to the Valley and I think it doesn't get as much traffic which is a major consideration. This might be a really good choice for you. I personally love the South Entrance, because I love to see the Sequoia Grove plus this takes you in past Glacier Point, which is (IMO) the most gorgeous view in the park. There is also a lot of hiking that starts at Glacier Point. This way in is also least likely to make me car sick. However, it's about an hour's drive from the South Entrance into Yosemite Valley - and can be much longer on weekends when there is tons of traffic - so if you plan to go into the valley every day, this might not be the best choice for you. I think the Big Oak Flat entrance gets traffice from San Francisco so I think I'd avoid that one if I were you. I've heard that the drive into the valley from Tioga pass (east entrance) is beautiful, but I've never done it and so I'm not sure how long it takes.
Make sure you check Yosemite websites for the exact time period you plan to be there. Some parts of the park are under renovation (Sequoia grove is right now I think), and some roads are only open seasonally, so do your homework. The park is worth the effort!!
ETA: The rest of the posts are correct about booking early. I've gone several times. I stay in the park, not outside, but my experience is that in order to get the campsite I want, I have to book online exactly 365 days in advance (the 1st day the reservations open for my visit), otherwise, they are full. So, I hope that you are planning now for next summer, not this summer.