I didn't even notice you were in Elk Grove. I'm just north of EG, but have lived out there a long time. EG High School class of 91! ha ha.
Anyways, I've been out to prairie city and it seemed to be more geared towards quads and dirt bikes and things like that. However, there are a few obsticles for "larger" 4x4's, including the mini-rubicon, although you probably don't want run that one with a stock anything.
What year/model is yours? I've got a 97 SR5, V6, 5 speed, 4x4 with the stock 15" wheels. Not the best, but it's still quite capable!
If you've got a 3rd generation Runner you may also want to check out yotatech.com, if you haven't already. It's primarily a 3rd gen board.