Well- the waypoints that Ian collected are still on the site. I'm sure that you could find an Xterra owner (or a Jeep owner) who'd like to hit these incredible trails again.

Mile-Hi Jeep Club has a large offroading event in Gunnison, CO from July 23-30 this year that looks like a lot of fun. It appears as though they allow any kind of 4wd vehicle. It ain't cheap though and they limit the number of vehicles attending (pre-registered only).

http://www.mhjc.org/calendar.htm

Dave