I don't normally recommend places I haven't visited myself but if you're going to be in San Francisco, you should check out Kawika's Ocean Beach Deli, where you can get a sandwich on home-made gluten-free bread.
I learned about Kawika's because it's run by a college friend of mine, who is gluten intolerant, and her husband. She says they make white bread and a dark multi-grain bread in dedicated machines. In my experience, it's rare to find a place with home-made gluten-free bread.
They also offer gluten-free desserts, salads and beer.
The deli is located at 734 La Playa St., which looks like it's near Golden Gate Park. I wish I was planning a trip to San Francisco because I'd love to check it out.