Quiet, Chill Place to Watch the Fireworks in San Francisco for the 4th

Just a caveat: I grew up here, and I can remember maybe four years that we weren't completely socked in with fog on the fourth (it's a running joke in my family), so whatever you choose, I'd advise anything that costs a lot of money. If you're dead-set on fireworks, then dinner cruise on the Bay might work.

There will be five of us, and we're trying to get back to the Castro with a minimum of fuss afterward Difficult-to-impossible given your other criteria. And what everyone else has said about the weather - a couple of years ago, we were at a friend's on Cathedral Hill (penthouse in a tall apartment building), and the fog was so thick we couldn't see the building across the street. The fog didn't even change colors that year. For the best chance actually seeing fireworks and not just colorful fog, Sausalito or Jack London Square are your best bets. Both will require driving, or ferry+ transit to/from the ferry dock to the Castro, and both will be crowded. (Seekrit: We watch fireworks from a corner on Potrero Hill - it's not a Destination, more of a neighborhood spot, and it is a fairly easy shot from the Castro, depending on your mode of transit - a car would definitely be easiest, though - and in good years we can see fireworks from Aquatic Park, Sausalito, and Jack London by wandering from one corner to the other. Memail me for the location if you want. Fog can still fuck it all up, but it's like a minute from our house, so it's usually worth a shot for us. YMMV.)

If it's foggy, you won't be able to see them from anywhere. If it's not foggy, Dolores Park is a lovely place to watch from, and it's right in the Castro. Depending on their mobility limitations, it could be tricky, and there are generally some crowds, but the corner of 20th and Church should be reasonably accessible and a beautiful view if there's anything to be seen.

I was coming here to say what everyone else said, no fireworks, too foggy. If by some miracle it is clear, one thought that came to mind was The Top of the Mark at the Mark Hopkins. Great for drinks and good views of everything. Climate controlled, elegant, quiet. Then, as it's a hotel, take a cab back to the Castro. You could pretend you have no idea about fireworks and fog, plan for drinks at the hotel, and when they don't appear, everyone will be appropriately mellow so it won't matter so much. http://abclocal.go.com/kgo/feature?section=news/local&id=6868364.