In reply to Chive Talkin\':
The 'classic' place to camp for all things circle-related is at the Barge Inn:
https://www.the-barge-inn.com/
The best site to keep up to date on circles, and if you can access them is:
http://www.cropcircleconnector.com/2019/2019.html
I used to live in Oxfordshire and spent a lot of time visiting the ancient sites, and visiting circles. I don't believe they're in any way mysterious; I believe people make them, but I loved the interplay of it all: people (artists, in a way) make the circles, and then the people who love woo interpret them to be from aliens, etc.
As for Stonehenge, I find it sad and disappointing. It's too busy and next to a main road. If you visit, be sure to wander off into the wider landscape where fewer people go. There are plenty more barrows and earthworks there. It's also worth visiting some of the other Wessex sites that I think are more atmospheric: Avebury, West Kennet Long Barrow, Waylands Smithy, Devil's Den, Windmill Hill, Liddington Hill, Whitehorse Hill, The Wansdyke, Adam's Grave. The Modern Antiquarian is a great resource for info:
https://www.themodernantiquarian.com/site/424/southern_england.html
Be sure to pack your walking boots. There are some great long tramps to be had in linking some of these ancient sites.
Post edited at 10:15