I-90 east to Wall Drug, then SD-240 through the alien-planet spires of Badlands National Park. A must-do day ride.
Easy. Interstate cruise and a wide two-lane loop. Anyone comfortable on the highway can do this.
Gas in Wall before dropping into the park. The loop is 30+ mi of nothing — do not enter on a quarter tank.
Wall Drug and Cactus Cafe in Wall are the only real options. Bring water; the visitor center has vending only.
Early morning or late afternoon — mid-day the pavement radiates like a griddle and there's zero shade.