"FourWinds suggestion to, "...arrive by shuttle from one direction and then leave by a different one, giving you a good fairly long distance view of the monuments from different directions." is also beautifully simple."

... and keeping the simplicity, but adding to the experience, the journey to and from could be circuitous, to visit various points, with a continuous commentary.... and could allow people to jump on/jump off as and whenever they chose...

Some, many, would choose to alight early and walk, to experience arriving at the monument early. The less able would stay on right to the main disembarkation point.

The shuttle buses needn't just start and end at the visitors carpark. So long as they were the requisite light design they could run from Salisbury... or Bristol....