I based my walk on mostly 2 day walks, with a middle overnight stop, travelling to and from the end points. However there are other ways of doing it.
Of course it is possible to do the whole route continuously and I met people doing just this, carrying everything they need (including tent) for the 200km journey. There are companies going west-east that carry your luggage from one overnight to the next, so you only need to carry a day bag, but nobody doing it east-west yet.
Here is a suggested breakdown in groups of mostly 3 days, with 2 overnight stops. This avoids some of the longest day walks and gives 13 days walking and 9 overnight stays. Overnights in italics, Good main line station connection thus //
- // Tring circular (as day 1) – Wendover – Princes Risborough // (8.5-7-7 miles)
- // Princes Risborough-Watlington-Wallingford-Goring // (11.5-11-7 miles)
- // Goring-East Ilsley-Wantage* (30 min bus to Didcot //) (7-10.5 miles)
- Wantage-Uffington-Chiseldon-Avebury (30 min bus to Swindon //) (10-11.5-10 miles)
- Avebury-Upavon or Netheravon-Stonehenge (30 min bus to Salisbury //) (13 or 15-12 or 10 miles). This goes by a more direct route than days 10 to 12.
*You could stay in Wantage and explore the town and area before leaving for Didcot
The direct route from Avebury to Stonehenge omits an overnight at Pewsey and more closely follows the ancient route. The idea would be stay overnight at Avebury so you have time to explore it and the nearby monuments such as West Kennet and Silbury Hill, then make an early start over the Downs to the Vale of Pewsey. See the route on OSmaps here.
The X5 bus runs hourly from Swindon to Salisbury and vice versa (but only roughly 7:00 to 16:00 Mondays to Fridays) but usefully stops off at many of the places along or near the later part of the route including Chiseldon, Upavon, Netheravon, Marlborough (bus links to Avebury), Pewsey // and Durrington Walls (for Stonehenge).