London to Cumbria ~300mi - Any route planning tips?

today should be renamed 'national coincidence sunday'

the coincidence relevant to this thread is someone I know is planning to ride from central london via epping forest and then all the way back up to cumbria/keswick. but I think he is taking a more leisurely 5-7day ride instead....
http://www.homeofmillican.com/
(can't find exact link to ride outline!)

also point 'B' on the map is like a 15minute ride from my front door, weird or what O_o

How did the person you know get on in the end?