Dorst Creek in Sequoia NP is the only campground in the Park that takes reservations. In addition it is only open three months, and thus still has a nice feel to it if you arrive early in the summer. The main loop for rvs is crazy with generators and the lot, however site #105, in loop B is a 70' pull thru, no generators, and just outstanding. The trees are amazing.
For Yosemite, Wawona is the place for us, the valley is just insane. Site #53 is along the river, and not as crowded as other sites. This is a roadside site, and I use three planks to level up.
Both Parks have different booking windows, best if you reserve at 7 a.m. when the window opens.
Our 5er is 30' as well.
'09 Heartland Sundance 285bh, '08 CTD