300 miles, huh? That's the same as me! At least St George & Cedar City are nearby, you just need to hook up with some locals & findout where the trails are. Then tell the rest of us!
There are a few trails down that way in what is called Hog Canyon. The Utah 4-Wheel Drive Association had their Fall Trail Ride down there last year (IIRC). There is a 4wd club down there, but I can't remember the name. I know one of the members' last name is Black (Gee, I sure am helpful ).