We visited the park in early Sept and found it very relaxing (if not a little too relaxing) - would have been lost without a TV and found ourselves venturing the 20 mile round trip to Dumfries each day just for something to do.
You need to pay for a pass to get in to entertainment at night, which is great if you like agadoo and cheesey "Abba" type bands with lots of kids dancing.
It is a nice site, and the people are mostly very pleasant also but if you want some action, might be better to travel a few miles further south.

Not recommended for teenagers but ok for families!