Heather and I did this event in 2013 after I finished filming and she came down from controlling at Brampton.
We wanted to get some footage of LEL cyclists in London, and Delph Cyclist kindly obliged. The central London prologue overlapped with the first starts, so I concentrated on Loughton, and the Freecycle footage illustrated that aspect of the ride.
We really enjoyed it. It's difficult to get a feel for the layout of London, as I tend to use the Underground. The main sights are surprisingly close together.
I've got a flow worked out for the weekend. Friday; drive the 200 miles to Waltham Abbey, arriving at my hotel at 10pm, to avoid traffic on M1/M25. Saturday; film at Check-in. Sunday; film early starts and depart.
I'd like to do other things, such as film the welcome party, or the Freecycle. But the logistics would just deplete my reserves.
If you're staying in a more central location, it could work well. I'd be interested in some footage of the event.