The Wandle Trail, which goes through South London, is relatively short but does not lack in great views. Plus, it's quite flat, so whatever your level as a rider may be you will most probably find the path satisfying. Its total length is 12 miles, from Wandsworth Town railway station along the Wandle River, through parks, wetlands, and a nature reserve. There are numerous Santander Cycle stations in Wandsworth where you can rent yourself a bike. Keep in mind though that there is no docking station further south, so you will have to double your workout in order to bring it back to the dock.