In reply to Fenda:
You could quite easily do a section of the North Downs Way, various bits of it pass by areas with stations, while it's not strictly Kent Downs I'd recommend the section from Caterham to Tanners Hatch Youth Hostel as being nice, you can then walk from the Youth Hostel to Guildford or one of the other stations in the area and catch a train back in. It's probably the best section of the whole route.
