rides near Brigham
There are some trails up on the mountains around the "B" and the "I". Also there is a single track trail system that leads up to Mantua on the south side ot the canyon with about 12 stream crossings(bridges). And if you don't want to come back down the singletrack from Mantua there is some double track on the north side of the canyon. Sherwood also has some great trails, although I was up there the other day and the grass is getting really tall, better wait for fall for this one.
All of these rides are great, I usually ride these a couple of times a week, but they are not all down hill, but the climbs make the downhill that much sweeter.