I'll just gush a bit about the Ridge to Rivers Trails in Boise. They're fantastic. The extensive network of trails in the Boise foothills down to the greenbelt along the river makes exploring this area very accessible and enjoyable. I have yet to try all the trails, but have really enjoyed the Shaw Mountain and Oregon Trail areas. For those who visit Boise and are interested in seeing what trail running/mountain biking options are out there, check out the link: it will not disappoint.