Went to Castlerigg for the solstice a few years back and it was excellent (I know you said it was excluded though). A fine gathering of all different types there with drumming and other musics going on too. Very family friendly atmosphere too. The bonus was that it wasn't cloudy or raining so had a wonderful view of the rising sun.
Was talking to a bloke who went there every year and he said it was the first time in 20 years that it wasn't cloudy that morning.
The beautiful low lying mist down in the valley also made it a very magical experience! Would definitely go there again for the solstice!
Only slight concern was that people had built a bonfire very close to the circle itself. I have nothing against bonfires, in fact I love em, but just thought it was too close to the archaeology for my liking.