A list of good biking options in Vacaville.
MOUNTAIN BIKING:
1) Lagoon Valley has miles of trails, both singletrack and fire roads.
See: http://vacaville.wikispot.org/Lagoon_Valley_Park
2) Rockville Regional Park: http://vacaville.wikispot.org/Rockville_Hills_Regional_Park
http://www.fairfield.ca.gov/gov/depts/pw/open_space/rockville_hills_regional_park/default.asp
ROAD BIKING:
1) Pleasants Valley Road out & back to Lake Sonoma.