Thanks Scubi, was just making a correction when I saw your post. I described David Dawson as curator of the Wiltshire Heritage Museum - he is in fact the Director (have edited my original post).
Cost was something that was discussed yesterday - it hasn't been finalised yet but as the ticket also includes entrance to the Witlshire Heritage Museum, my thoughts were that anything less than £15 would be unrealistic. I've posted a link to the Stonehenge-Avebury bus website and there is also a Facebook/Twitter site called Henge Hopper so people can check there for updates.
The idea was to be a flexible as possible in terms of dropping people off and picking them up within the constraints of a time-table. It all needs fine tuning but David Dawson has worked hard to gather together various bits of funding and is also willing to be one of the drivers - all very positive but needs support and input from as many people as possible.
I feel very lucky to have been included on the trial run which was to some extent 'by chance' as I had intended to go to Devizes that morning anyway. My way of saying thank you is to bring the project to the attention of as many interested people as possible.