How about a night at anchor? You should be able to find spaces at Angel Island's mooring field in the middle of the week, though I don't know that reservations are possible.
Since you've already been down the canal in San Rafael, you probably don't want to backtrack to Loch Lomond. With two days to kill between SFYC and Richmond, you could easily hit the Estuary and visit Encinal or Oakland YCs. The Giants are in town for both 9/25 and 9/26, so IF you can get reservations with South Beach Harbor, South Beach YC would be fun. Their new clubhouse is great.
BTG