It depends on what the children are like imo.
DS1 also 14 has a fantastic bunch of friends...boys and girls and that is exactly just what they are, friends. DS has a girlfriend, but I know darned well it hasn't got to that stage and won't for a long time. They are all just too sensible. I know I may be being a little naive here but I do know my son.
He has been to a boy/girl sleepover (in massive country house . The parents were there, but on a discreet level. He shared a bedroom with 3 of his male friends and I think most, if not all of the children did the same ie girls with girls and boys with boys.
At this age you do need to trust them a bit. If you are worried about hormones taking over then have a chat with your daughter. They will 'do it' one day and there won't be much you can do about that, but if they know all about unwanted pregnancy/STD's/contraception, then they are much less likely to get into trouble. They could do it anywhere!
Having said all of that, I would encourage DS to camp very near to home (ie the field next door )
My sensible mum head says he would be absolutely fine...knowing his fab friends and how sensible and level headed he is, but my worry wart mum head would stay up all night ...worrying