The White Rim trail is awesome, but for some routes a bit shorter, try: (all of these are no problem for your T4R ORP.)
- Long Canyon, on the way to Potash
- Gemini Bridges, west off of 191 7 or so miles north of Moab. Both of these first two trails end on the paved road on top of the mesa which leads to the Island in the Sky district of Canyonlands NP.
- Hurrah Pass, south on Kane Creek Boulevard out of Moab. Gets tougher on the west side of Hurrah Pass, but the view from the pass is awesome, so worth going that far and turning around.
- The Schafer switchbacks, between Potash and the top of Island in the Sky. Good road, but a lot of exposure. Awesome scenery. No permit required, just the park entrance fee.
- The Willow Springs "back door" entrance to Arches NP. Turn east on a BLM road off 191 about 5 miles north of Moab. Joins the paved Arches road at Balanced Rock. A great way to get into Arches when the RV's are lined up for a half mile at the main entrance. Just before you get to Balanced Rock you can take a short side trip to Eye of the Whale Arch. A little rougher, but no problem for a stock T4R.
Have fun! I second getting the Wells book.