Nice safe trip. You can fly airport to airport on that route, and as long as you are a few thousand feet, always be within gliding distance of something, between all the closed military fields, and the active small stuff. I like going up that way because to get there, I go up along the coast of HAF, and SFO, then do a little bay tour lap or two before heading on up.
Petaluma is a good stop. Cool little pilot shop on that field, and good eats too. Up in that area, I'd suggest you go to Sonoma Skypark, next time you are with an instructor. It is a great field to see why you practice short field work, and a steep angle to clear stuff at the end of the runway!
A little up past STS, Healdsburg and Cloverdale are both fun little stops in the area, and cheap gas.