Author was in the middle of prepping for the NYC marathon, so they were in decent shape physically.
My fat ass would have given up before I even reached the Bay Bridge.
That reminds me: the author did not mention how they crossed the Bay Bridge. There is no cycling path from SF to EB AFAICT.
I biked with the author from SF to Sacramento — we went up to Marin over GGB, then over the Richmond–San Rafael bridge to the EB
> My fat ass would have given up before I even reached the Bay Bridge
Cycling is a fairly low-impact activity for your body, and is a great way to get some exercise if you are out of shape, with a fairly low risk of getting exercise-related injuries. (Compared to, say, running)
The only thing you'll really need to "train" are your "sit-bones". A good, soft-ish, wide saddle will help, as well as padded shorts. In fact, for your comfort, padded shorts are a must-have.
There's a separated bike/pedestrian path on the Dumbarton Bridge, although that's south of SF. (When I was working at Sun Microsystems nearby, I saw the pedestrian path and randomly decided to jog over the bridge. I discovered that the bridge is a lot higher in the middle when you're jogging than when you're driving, so there was a lot of uphill.)