Paradise Loop

This is one of the more popular routes in Marin. Probably because it's fairly short and not very hilly. There's also a cut-off option to make it even shorter. Plus, you get to ride through one of the richest areas on the planet. And if you're really lazy, you can take the ferry back in Tiburon.

But I'm not too into it, mainly because it is so short and you only get to go up Camino Alto one time (which is one of my favorite roads in Marin). An extra bonus though, is a section of the road got washed out (at least) a year ago, and they seem to be in no hurry to fix it...so even less traffic!