Two principal scenic drives are open to vehicles and bicycles, both starting near the visitor center. The 21-mile Ajo Mountain Drive takes you through a spectacular landscape of steep-sided, jagged cliffs and rock tinged a faintly hellish red. It's a well-maintained but winding and steep gravel road navigable by regular passenger cars (not recommended for RVs over 24ft long). Ranger-led van tours are available from January to March. The other route is the 37-mile Puerto Blanco Drive, which has several spectacular viewing points with informaton about the Sonoran Desert.
Unless it's too hot, the best way to experience the martian scenery here is on foot. There are several hiking trails, ranging from a 200yd paved nature trail to strenuous climbs of more than 4 miles. In winter, free shuttles lead to the trailheads Senita Basin (Tuesday and Friday at 8:30am) and Red Tanks Tinaja (Monday and Thursday at 8:30am), from where hikers traipse back to the campgrounds. Bring a topographical map and a compass whenever hiking cross-country, and know how to use them – a mistake out here can be deadly. Always carry plenty of water, wear a hat and slather yourself in sunscreen.