I live on the lake in Huddleston. Smith Mountain Lake State Park may be your best bet so suggest you try and contact them. They have a decent campground, cabins, large beach, huge boat ramp and a lot of wooded areas. There are a few (not many nowadays) marinas that have lot's of RV's on sites but not what most folks would call campgrounds.
There is a new campground/RV park called Sweetwater RV Park on White House Road. It has only 18 RV sites and is pretty much in an open area. They just opened this spring and I have not seen many folks using the place yet.
'07 Country Coach Allure 470 Siskiyou Summit #31578, Cummins ISL 425; 2014 Ford F150 toad; Air Force One Toad Brake.
Glen Allen, VA; Smith Mountain Lake, VA.