I've been looking for astronomical alignments here for years and have found none bar a few possible lunar standstill points.
There is certainly no obvious Solstice alignment anywhere.
Terry Meadon has a theory about shadow casting but with 100 stones in the outer circle it would be a suprise if there were no accidental ones.
Villagers do not want a camp site for fear of it becoming a permanent travellers site.
Camping in the WHS is now banned as no one turned up at county court 2 years ago to challenge EH.
Overnight camping in the NT car park has now been restricted by the council after demands that it be made available for Pagan events.
NT byelaws say only 15 nights per annum are allowed and the NT decide when to be flexible.
The only real option is for a park & ride for solstice.
I offered NT a friends field in Monkton to use for that purpose and they turned it down flat.
I recently turned down the invite to a Round Table meeting about solstice as I don't see the point.
NT will do what they want no matter who says what.
PeteG