Sorry Justin, I couldn't resist throwing in the livestock picture, especially since it was taken in Rattlesnake Canyon. As for your question - yes it can usually be done by a stock Xterra, but be advised that there are a few rocky patches. Also, weather can make a difference, especially if there is a a lot of water. It's a fun run, though, with lots of variety in the terrain and trail.
If you want to see some pictures, here is a link to a gallery of shots from my first Xcursion with the club, which was Rattlesnake Canyon in February of 2006.
http://frankbaiamonte.smugmug.com/So-Cal-Club-Xterra-SCCX/Rattlesnake-Canyon-Feb-2006/Here is a link to the same run in February of 2007. That time we did not end up in Big Bear but turned down Burns Canyon instead. The pics themselves may not be all that great in these 2 galleries, I think I was still scanning film in those days.
http://frankbaiamonte.smugmug.com/So-Cal-Club-Xterra-SCCX/Rattlesnake-Canyon-Feb-2007/You may also find something in the Pics/Videos Forum here, but I'm not sure they go back that far, we lost a bunch of stuff when the site crashed a while back.
Edit to add: There are at least 3 threads of pics from the Dec 2008 run on this page:
http://www.sccxterra.com/smf/index.php/board,4.80.html