Here's someone's blog with some good ideas for trail runs:
http://letstrailrun.org/
I've been sporadically taking part in the marathon training runs with the Loma Linda Lopers and this morning when I got done I found a flyer for the Desert Edge Challenge, which is a 5K/10k/15K run in Banning on Sept 28th - easier than the tram run - the 15K has 1000 ft of gain over the first half and then it's downhill for the second half.
