See if you can find out if there are any cycle club swop meets coinciding with your visit,may pickup something tricky to get here
Yes leave plenty of shopping time
One piece of advice.... be carefull where you stay in San fran. Can be a bit of an eye opener.
Take it from me, I had a weekend there at the end of a job. Was on my own and didn't really think about areas. I didn't twig until I went out for a beer in the evening and walked into some very 'specialist' establishments
Got to do the Alcatraz trip plus a boat trip out under the bridge.
The trip you are doing is one that I've thought of many times. Sure you'll have a cracking time