I grew up in north county and remember driving around Elfin Forrest, Questhaven Rd. I moved away then came back a few years ago. That San Elijo Hills development was a real shocker. I have only been down Elfin Forest between San Marcos and Escondido once in the last nine years since coming back, and Questhaven not at all. I see on Google Maps that Questhaven is now closed to cars. Can you still bike through it?
http://goo.gl/maps/Mli8W