What do you mean by best? The park is quite large north to south so the area is big. The campground just north of Sandstone Visitors' Center is pretty nice but has limited amenities however it is free. In my book free is best. Tamarack is just west of there, also free but noisy.
I don't believe the RV park above Sandstone has electric connections. I would call ahead to be sure. There is a state park, Little Beaver, not too far from Grandview and Sandstone off I64 going west. If you have a large RV the roads can be a little challenging, but foks do it all the time! I see others have suggested Cantrell's and Bluestone, both near Hinton and on the southern end of the park. Please know that the Tamarack is a lovely destination for arts and crafts, but the RV "accommodation " is a parking lot. Another remarks on the size of the park and they are right! You must do a search nearest the areas you choose to visit. There are campgrounds from Summersville to HInton, sprinkled throughout. They widely vary in amenities and accessibility. The area is moreso geared toward the adventurous.
Cantrell ultimate rafting has RV campsites & only 1.5 mile from new river bridge..
Pipe stem park or bluestone park
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