Originally Posted by Paul Glezer
3.5 miles on a bike, will go by QUICK. Super good warmup and cool down.
But 3.5 miles by bike in the hills of San Francisco might be torture; depends on the route. Ryan, I'd get ahold of one of the SF bike maps, which will show elevation change, to check if there's a reasonable route for you. If you can find a basically flat route, it should be fine.