I've done this, but in the other direction, by public transport. Neither end of the Ridgeway is particularly convenient for public transport. Avebury is quite

I've done this, but in the other direction, by public transport. Neither end of the Ridgeway is particularly convenient for public transport. Avebury is quite close the western end, and has buses to Swindon (and then trains to London). It's also well worth visiting: a highlight of the trip. At the eastern end you're not so far from Tring train station. Accommodation is a bit sparse until you get close to London, so it will tend to dictate how far you walk each day. However there are companies that will arrange it, take your luggage, and pick you up / drop you back on the trail. Some B&Bs can also help with this. (We just carried our stuff and walked to the places we stayed)