First off, you'll want to be in great aerobic shape! If you live close to Barr trail, try to train on it every weekend! If you can't do that hit the big hills where you live and/or get on a treadmill and set it to 15% and go, go, go until you can't stand it any more...
I think John V posted about an Ascent treadmill simulation on this site recently. Check that out too.
Good Luck! might see you on race day if my sprained ankle lets me:(