The 5,312 acre Santa Ysabel Open Space Preserve, located in the extremely scenic mountains between Santa Yasbel and Julian about 40 miles northeast of San Diego, is one of the prettiest preserves in the county I have seen to date. While fire roads exclusively make up the designated trail system here, you will most likely not mind at all as the beauty of the place makes up for the lack of singletrack options. The rolling open grasslands and oak groves remind me a great deal of Northern California. You can get in just under 20 miles of riding if you do all of the loops and out and back sections. It is well worth a visit, but you will have to make it a weekend as the perserve is currently only open on Saturdays and Sundays from 8AM to Sunset.