When i was training i cycled from Home to Kings Cross Station, took the train to Sandy then cycled 12 miles through lovely country side to Little Gransden. It helped me prepair mentally for the learning. Driving is a stressfull thing and it doesnt put you in the best frame of mind to take all the info in i found (unless it was raining
). So if your not against cycling then any of them would be easy to reach. Gerrards Cross station to Denham is only a couple of miles, likewise Boreham Wood to Elstree Etc!