finish: Oxford, St Giles
distance: 54.7 km
Mainly flat cycling route except for a little bump at the end, called Boars Hill. The first 12 km can be unpleasantly busy with cars, but as soon as you leave the B4449 onto the single track road, it's much quieter. Another very nice stretch of single track road between Witney and Stanton Harcourt has long escaped my attention, but is very worthwhile. Even if your bicycle doesn't have any gears this route shouldn't be a problem.
Route map:
This route is also published on MapMyRide