Originally Posted by FATFlyer
It seems to be from rap and hip-hop. There are songs with titles like "I Love Cali in the Summer Time!" and "Cali To NY".
Yep. Cali has been a hip-hop term for over 10 years now.
Now, here's my standard SF advice: if you are in reasonably good shape (as you say), rent a bike. There's no better way to tour SF, in my view.
http://www.blazingsaddles.com/
You could ride from Fisherman's Wharf (and any San Franciscan will tell you that riding away from FW is a good idea) through the Marina & Presidio, then across the Golden Gate Bridge and to Sausalito. You could take the ferry back from Sausalito to FW. On this route, you see, at a leisurely pace, over 50% of the best scenery the Bay Area has to offer.