Originally Posted by Shimpie
Coast Highway is a good ride. Take Via Del Valle west to Coast Hwy. You can can go north for a flat ride, with a bike lane even. You'll get your 20 miles on this stretch no problem.
Now if you're adventurous and really like a challenging (nearly impossible) hill, you can attempt Torrey Pines. Simply go south on Coast Highway. At the top of the hill is UC San Diego, which has lots of roads with big shoulders/bike lanes to cover. I haven't ridden the Torrey Pines hill yet cause I'm a wimp. What goes up must come down, and the "down" part is what scares me. You can tell me all about it if you brave it.
-Shimpie