I've been browsing through messages to get into the mood for camping and found this one. Sorry for digging up an oldish thread but the rose tinted travel sunglasses have got me misty eyed!
We've camped in Denmark a few times, with and without kids. I would agree with previous poster about the facilities at camp sites being excellent, we often find them better than most UK sites.
I would really recommend Charlottenlund in Copenhagen but you will need to book, the earlier the better, look at doing it now. We booked definate nights there for the first part of a trip and then made the rest up. It is a great site- small but busy, very cosmopolitan with different nationalities, next to a beach and 20 mins bus ride to the centre.
When are you hoping to travel? If it's August then the Danish school holidays are finishing so campsites are less full but still good weather and facilities.
We also liked Trelleborg and Ribe. The Viking ship museum at Roskilde was fantastic, and we liked the castle at Helsingor (good cycle or train ride up to here from Copenhagen), Egeskov slot on Funen, a trip to Aero, especially to Aeroskobing (this has great camping but can be expensive to get to, but a day trip is well worth it, think there is a ferry from Sonderborg, but we went from Svenborg and Faaborg), the outdoor musuem in Arhus, the Church and graveyard in Jelling and also the 'tollund man' in Silkeborg.
I didn't like camping at Billund- it's a big site and right next to the airport so very noisy but it is convenient for legoland. The last time we went, we went instead to a site a bit further away in the 'Danish Lake District' and made legoland a day trip from there (as well as using it as a base for Arhus and Jelling). If you do go to legoland, it's often possible to buy tickets from campsites, this will save you a lot of queuing.
My fav camping sites were Charlottenlund, Mons Klint, Aeroskobing and Faaborg.
I would go every year if I could.