Current status and next rides planned (the blue boxes are some of the tiles I need to tick off):-
05-NOV: Blue (Woking) is a 70km ride with only 300m climbing to be done tomorrow.
12-NOV: Red (Lower one, Epsom/Leatherhead) is 50km and 521m climbing
19-NOV: Cyan (Surrey Hills) is 55km and 734m climbing (including the 18% climb of White Down)
26-NOV: Dark green (Croydon, Caterham, Coulsdon) is 60km and 992m climbing (I'm quite unfit and quiet heavy so that'll be fun, purposely routed it repeatedly across the North downs ridge)
Then the red run up to Waltham Abbey is 75km (or 85km if I have time and don't get the train home from Waterloo) and is part of the rides I need to do to connect a large clump of tiles up near Henham to my main cluster.
After that I'll aim for the NW section (Wembley, Ruislip, Rickmansworth, etc), then North London (Edgeware, Barnet, Enfield), NE/Essex and round to East London and SE London. By my reckoning it's ~20 more rides to cover all tiles within the M25.
After that I'll go for pushing my cluster out West (Reading area) and North (Henham and on up to Cambridge) or targeting max square increases with rides in new areas. I'll soon (6 months I suppose) hit the limit of what I can add in the 6 hour window I have once a week without spending too much of that time getting to/from new tiles.