If you're coming from the south, seems your official options are :
1. Ride there - which means scoffing your breakfast and starting before dawn for a lot of people and thus taking lights. Even though it's only 10 miles for me, allowing an hour to take it easy means I need to leave before dawn - 4:45 latest to load at 5:45 for start at 6:45.
2. Drive and park car all day at various places- not an option for me as my partner will be driving and can't leave the car all day
3. Get a lift, forget lights, scoff porridge on the way, and get dropped at official points south of the river, then ride 5 miles or so:
3.1 Dropoff B (Jamaica Rd) then ride over Tower Bridge or through Rotherhithe Tunnel (!)
3.2 Dropoff E (Surrey Quays) then ride through Rotherhithe Tunnel (!!)
3.3 Dropoff D (Blackwall Lane) then get the cable car from the 02 to Excel and ride from there; while its not mentioned, I would assume Greenwich foot tunnel will be closed.
While I suppose it will be difficult for them to prevent dropoffs elsewhere, you get the impression that getting North of the river is going to be impossible.
I guess at the moment I'm thinking of either 3.1, or alternatively driving over London Bridge (Waterloo, Blackfriars and London Bridges stay open as they go over the route), and jumping out wherever we get stopped!
I think Julian said he had a cunning plan involving coming in from West London....anyone else got any ideas/suggestions?