Chico and the Man wrote:
There's a bay "trail" (more of a bike path) that goes along the bay to the south of the airport. There are a number of hotels on the bay within 1-2 miles of the airport that I've run from. I'm sure some of the South Bay guys will chime in with potential specifics.
I've run from the SFO airport along this path. I weaved my way out of the airport to the left, ran along the shoulder of S. McDonnell Rd., and saw the bike path to the left along the bay (by Old Bayshore Highway). I went for a 60 min run (30 min out and back). I got to a point where the path sort of ended, and I wasn't sure where to go (maybe it continues on the sidewalk?). I turned around and ran back. I think I found the route from Googling paths from the SFO airport. I left my luggage with my spouse-- cleaned up with power shower wipes when I got back to the airport. Some of the nearby hotel may have day or gym passes too, so you could look into that.