I stopped in at Sonoma Valley Portworks in Petaluma today after having lunch at Aqus Cafe about a half block away. It's an attractive industrial space where a husband-wife team make and sell port. I'm not an connoisseur of port, so you'll have to make your own judgments about it, but I'll say I liked it and it was "fun" to taste. One had dark chocolate infused into it. I bought a bottle of their non-port and non-alcoholic Sonomic Vinegar, which is Cabernet juice, processed somehow to make it a bit thick, with a bit of vinegar added. It's delicious and would be great over any number of desert items.
Within about a block area are Sonoma Valley Portworks and two good cafes, Aqus Cafe where I had lunch and also Luma (both recommended by the owners of Sonoma Valley Portworks). I think you'd like to check out this area of Petaluma.
Sonoma Valley Portworks
613 2nd St, Petaluma, CA
189 H St, Petaluma, CA 94952
500 1st St, Petaluma, CA 94952