From 4 Corners you pick up the trail directly across from the tables and kiosk. You climb up to the ridge and then go under the the power poles. Keep a lookout for the trail entrance after passing the utility road. Raptor Ridge does have some exposed sections but nothing too technical, it does have a few steep sections so keep your speed under control.
This trail does get hidden in the spring by the black mustard that overtakes this park so hopefully it will get enough riders to keep it clear.