Now it's up to them:
For the non-Chain Gang members: We're the Chain Gang because we ride chain-drive BMW motorcycles, and the game is called "photo tag".
Take a photo of a landmark with your motorcycle showing, then other members figure out where it is, ride there, take another photo as above, and then they get to post another destination.
This is the only place I knew of to post some images easily, but I'll do something else soon.
I braved the coming storm to find the first location in the Presidio, and gave the rest of the CG a choice of locations. I only got slightly damp, and had a little cross-wind on the Bay Bridge and approaches.