One of the finest stone circles I have visited. Well, top 20 at least. ;)
As for Castlerigg - I think you need to play the waiting game combined with choosing the right day. We've been loads of times now, and find that - especially midweek (assuming it's not a holiday/festival) - if you hang around long enough, you'll get the place to yourself. We managed about half an hour one time! ;)
Greycroft is an odd one... Wasn't too overgrown when we were there. The power station is an imposing sight, and the eerie, rusting train that trundles past occasionally adds to the atmosphere of a post-apocalyptic landscape! Sort of. Maybe it was the blistering heat. ;)
There's some great roads around there - lots of them that make you feel like you're driving uphill when you're not, and vice versa. Luckily the roads were pretty deserted cos I had to stop halfway "down" a hill and let the car roll "up" in reverse! Small things, eh? ;)
G x