There IS availability at Camp Curry for July NOW.

If you book NOW, you will not be stuck outside the park, or constantly calling and hoping for something to "pop up".

To clarify about Camp Curry - it's an alternative to RV, not an RV site. We used to spend a week there every summer, growing up, and I loved it. Like camping, only most everything you need is provided. Great recommendation.

I think driving an RV in Yosemite in July would be a nightmare. And for RV newbies, a real mistake. BTW - on honeymoon in Yosemite, we had to stop to pull a couple out of their RV after their brakes gave out and they crashed coming downhill. How they managed not to go over the side, I'll never know.

Here is the direct link for Camp Curry

http://www.yosemitepark.com/curry-village.aspx

For Housekeeping Camp, see here (but they are booked for all of July)
http://www.yosemitepark.com/housekeeping-camp.aspx

For camping, see here

http://www.nps.gov/yose/planyourvisit/camping.htm

I am so surprised to see space available for Curry Village in July, and even for Yosemite Lodge in August. Now I'm thinking of going myself (I haven't been in about 25 years)