Trek San Diego has group rides if you're interested every Saturday. I haven't been on one but I heard they are pretty good if you're a new/intermediate rider, plus they always make sure no one is left behind. I believe they have 2 groups that go at different speeds (the slower one finishes in a little less than an hour for the 23 mile ride on the 56 I think). http://treksandiego.com/page.cfm?pageID=59

The Ranchos Cycling club also has group rides on the weekend that are longer and faster. http://www.ranchoscycling.org/rides.php They haven't posted the November ride schedule but if you're interested, you can email them. Again, I haven't ridden with them, they are quite above my level since I just started and only go about 10-20 miles a weekend

Also, on the other thread I mentioned the 56 bike path which is one of the rides Trek does. I have ridden it and it's very comfortable, definitely not a challenging ride though since it's fairly flat.

Enjoy your stay and stay away from Tijuana!