Lake Fairfax County Park might also be a reasonable option. I haven't stayed there myself, but it looks pretty decently nice from what I've seen online.
By the way, as an owner of a class C that happens to be exactly 32' long, I wouldn't worry too much about sites that are intended for "small RVs." In practice you'll find you can fit in most sites that could accommodate a typical mediumish travel trailer; you don't have the hitch and A-frame on the front to take up space, and you don't need as much room to maneuver in and out in general, and you don't have to find space to park your tow vehicle. That's not to say that every site will be big enough for you, of course, but there are plenty that are at most parks, even ones with generally smaller sites. Finding a place that is suitable should not be a great challenge.
