If you don't mind a little drive, Anza Borrego has tons of easy trails that will get you comfortable with your H2. They also have a training grounds area with varying degrees of obstacles. I am part of a FB group that is heading to Eagle Mountain bridge Oct 24. It is basically a beginners trail, stock trucks make it out there easily but there are side trails that you can take that will let you flex the suspension a bit.
Hey DaDankTank did you ever get someone to take you out? How has the H2 handled itself if you have? I just got my H3 and am looking to figure out what it can do as well. I have to take it to the dealer to get this airbag light off tomorrow but hopefully they can get it sorted so I can try to hit some trails this weekend. I read in the forum there may be a meetup later this month (not sure if its an open invite or if there is a cars and coffee type deal that people do for Hummers).