As we are right in front of the Alps there would be anything you could dream of...mud, dirtroads, different kinds of forests, rocks, a lot of small rivers. Terrain and landscape is comparable to colorado or wyoming. The problem is: Driving off the road is generaly not allowed and almost every single forrest or dirt road is equipped with a traffic sign, that prohibits entering it. So if you find one of the few legal dirt roads to drive into an area worth wheeling, you get illegal as soon as you leave the dirtroad and actually start wheeling.
But of course we know some nice areas to wheel, and of course we do use them. Still one has to be aware, that if you get into trouble with a hunter or forest warden, it can become very expensive. (OK, honestly in most cases they just yell at you to get the **** out of here, with your loud, annoying and all nature destroying shitpile...)
And then there are offroadparks as well. For some serious wheeling, that's where you have to go.
Where are you based at right now? If you want to take your XJ out for some wheeling i can certainly give you some information on where to go best.