Partway up the Needles Highway in Custer State Park, the road squeezes through a slot in the granite called the Needles Eye, and it's not unusual to find a motorhome stopped at the mouth and backing out the way it came. Over on Iron Mountain Road, the pigtail bridges curl back over themselves and a tunnel mouth frames Mount Rushmore at the far end. Those two roads through the spires of the southern Black Hills, more than any campground, set the shape of a week here in a rig.
The state posts the Needles Eye Tunnel at 8 feet wide and 9 feet 9 inches high, with Iron Creek Tunnel at 8 feet 9 inches by 10 feet 10 inches, both on the 14-mile Needles Highway, which closes to vehicles with the first snow and stays shut until April or later. Iron Mountain Road's three tunnels are only a little roomier. RV owners who've driven the park give each other the same advice, which is to leave the rig at camp and run both roads in a car.
The Wildlife Loop and its bison herds suit a car or something smaller, and the Rapid City campervan page covers that drive. For a motorhome, the park comes down to where it sleeps.
Custer State Park campgrounds, Blue Bell to Sylvan Lake
Legion Lake and Blue Bell both set their pads in ponderosa shade, and the state lists both as able to take large RVs. Stockade North takes any camping unit and Stockade South takes mid-sized rigs, while Game Lodge rounds out the electric sites a family wants after a day on the tunnel roads. Moving between them is a short hop on the park's main roads, so a week can split between the lake and the deeper woods without the rig ever going near the Needles.
Sylvan Lake is the campground people picture first, and it is the tight one. The state calls it not suitable for RVs over 27 feet and sends drivers in on SD-89 north from US-16A in Custer, the long way round. A family in anything bigger can still see the lake by day in the car, and two people set on sleeping beside it can size down to a South Dakota campervan.
Reserve the campsite before you book the motorhome, because the site decides how long a rig you can bring. Custer's campgrounds book through the state, online or by phone. Early-August rally week and the autumn Buffalo Roundup pull rigs and pads across the Hills at once, so a family week on those dates competes with the crowds for both, and the rally side of that is on the Sturgis RV page.
Hill City, Keystone and Custer resorts for the parked week
Plenty of families never move the rig once it's set. They take one full-hookup pad at Hill City, Keystone or Custer for the week, run the air through the afternoon, and drive the park and the tunnel roads by car. Any of the resorts below makes an easy first night, and if they're full when you roll in late, Game Lodge or Blue Bell inside the park is the fallback.
Rafter J Bar Ranch at Hill City spreads six camping areas with electric, water and sewer across alpine meadows under the ponderosa, and it's the name RV owners bring up first for a big rig. Mount Rushmore KOA at Palmer Gulch, also at Hill City, sets its patio pads in the pines, with deluxe sites sized for the largest RVs with slideouts on 50-amp. In Custer, Fort Welikit runs full-hookup 50-amp pull-throughs from the start of May to mid-October. Keystone, the town right under Rushmore, has smaller seasonal parks such as Rushmore View RV Campground, set beside its hotel.
Towables here are often delivered to a Hill City pad and set up by the listing owner, so nobody in the family tows. That's arranged listing by listing, and the reserved site and its rules still come first.
Mount Rushmore is the half-day out from any of these bases, the granite faces looking out over the pines above Keystone. If you bring the rig, the Park Service puts RVs over 29 feet and trailers in lane four and smaller RVs in lanes one to three, warns that larger-vehicle parking is very limited, and allows no overnight parking. The car is the easier way in, and the night stays at the resort.