They did make sites 24-70 all FHU a few years ago but they are also the most desirable and you better book 6 months ahead of time if you want them in peak season. I would stay away from sites 24-26-28-30-31 as there is a water treatment behind them and they can smell a little.
Sites 63-64-70-69-68-67-66-65-62 etc.. are all nice. I like 63 myself because there is a good amount of land between the next site and if you have kids they have a lot of running around room.
They have redone the welcome center and its very nice now unlike the little 10x10 hut they used to have where to get to the campground you literally had to drive across a little stream.
We go a few times a year up there and I always tell my wife the truck has earned its paycheck going up those roads.