The variation is generally in which rural route you wish to take to West Wickham avoiding Caterham, Biggin Hill and Orpington. Your preference for how to climb the downs is pretty much immaterial (although I know some very attractive routes that seem to manage to do it three times). West Wickham to Crystal Palace is the five mile suburban stretch, generally along wide straight roads with your goal of Crystal Palace always visible ahead. There are two options on climbing to Crystal Palace. Via Anerley or Beckenham and Penge. Anerley is slightly more direct but a steeper climb, Beckenham and Penge takes you close or through two shopping areas - Penge is funnily enough the grottier of the two but you'll be through it in less than two minutes. At Crystal Palace take the private toll road past Dulwich college and then through Dulwich village and on towards Denmark Hill - the last two miles have all been on 20mph roads through possibly the most 'pleasant' part of south London. From here you have three miles to the centre ofl London and whatever way you cut it it's probably your definition of grotty although it's all got character! All the routes are well populated with cyclists though and I don't think there is a swifter and more pleasant route from green fields to grot in any other direction from central London. If you think it's a goer I can give more specific advice on the nature (hills, rat runs) of the individual rural roads to the south and there will be plenty of opinions here on navigating south London. Unfortunately, there is hardly any 'pleasant' way into south London that doesn't involve a decent climb or two.
