If you continue south on SR24, you can follow the signs to Goblin Valley State Park (N 3835'/W 11040') where you'll find some really far out rock formations and an unimproved campground with pit toilets, picnic tables beneath cabanas, and fresh water. This state park is worth the trip.
Back to I-70's Exit 131. This time double back east on EM332, parallel with I-70, for a purely scenic trip. According to the map, two blue trails head almost due north from very near the offramp's access road, but I couldn't find them on the ground. About 4 miles east of the offramp, signage will point you toward The Sinkhole (N 3856'/W 11036'). The Sinkhole, a natural vertical shaft in the middle of a meadow, is surrounded by a split-log fence to keep the wild horses and burros that populate this area from falling in.
Continue northwest on EM332 and then more northerly past Bottleneck Peak to the junction with EM320 where you'll find another unimproved campground. EM332 turns slightly northwest, travels through a very scenic canyon down into Buckhorn Wash where you'll find a huge pictograph panel. For maybe 300 feet along the road on a towering vertical cliff face, hundreds of generations of Indians have drawn pictures and left messages for those who follow after. You'll want to spend an hour or two attempting to decipher the messages on the wall.
These two trips are just the tip of the iceberg of what's available for you to explore in the swell San Rafael Swell. You could probably spend an entire month here, exploring a trail or two a day, and still never see all that the Swell offers. You may even discover some cliff dwellings if you're lucky!