Agreed with another reviewer--this park is schizophrenic. The Jones Lake side is nice, but the location next to the freeway, train, busy access road, and public boat ramp/bait shack is unpleasant. Plus, the live-in manager and wife are some of the most hostile, unfriendly control freaks I've ever encountered in all our years of RVing. It's surprising because you get used to the friendliness in most RV parks--these people were rude not only to us but our neighbors in the park, and everyone we spoke with out on the fishing pier while we were fishing.
This was a good place to camp as far as access to Mt. Rushmore and Hill City, although we wished we had actually stayed in Hill City. Keystone is almost hilariously touristy. We kind of liked the train going by, and we don't mind bikers. We stayed here at the end of the Sturgis craziness, and everyone was in a good mood and having fun. Be sure to ask for a shaded site--it was hot when we were there and we missed having shade.