100 miles sounds long for Shafer... are you thinking of White Rim road? The Shafer switchbacks are part of White Rim, but typically people make their way toward Moab via Potash Road. It's paved at some point. White Rim is definitely doable in a stock 200, but it's pretty remote so go in prepared. Also, I'm pretty sure you need a permit even for day use so keep that in mind. It'd be a tiring but fun day...
A fun day would be to take Gemini Bridges from 191 into Canyonlands, explore some of the hikes/viewpoints, take Shafer Trail down to Potash Rd., Long Canyon up to Dead Horse State Park. There's a short, fun mountain bike trail in that area along with some amazing viewpionts.