Doesn't seem like a good match for a cargo bike which would take up lots of room in your apartment and be hard to get in the elevator. I prefer to use a regular bike with a rear rack and panniers for most shopping trips and I supplement it with a folding trailer for the few occasions where I need additional carrying capacity. If I lived in SF I'd probably use my folding bike with rack and panniers as my primary bike so it would be more convenient to use it in conjunction with mass transit (my folding bike and trailer fit fine in the BART elevators, but I have to unhitch the trailer).