I thought Caldons was closed - it was deserted last time I passed through - about a year ago. Soooo - I checked on Google and it is indeed permanently closed - but - you can camp there. This would be a wild camp since there's no facilities at all. There's a small campsite down the road at Bargrennan, though which is next to a pub and will take a few tents. Midgies are a bit mad around there, though....