The DERM website says, dependent on which campground you want, you can book from 3-12 months in advance. I've been able to book our sites online for June and July as well. I looked up the campsite maps on the website first and chose which sites I wanted. They tell you how many cars, campertrailers and people can fit on each site, and they give measurements of the site too. They also let you know if the site is shaded, whether it's suitable for a tent or campertrailer, and in some cases, where it is in relation to the river banks .
I came across a couple of flaws in the system. The first being that I had to book for 6 families, so when I typed in the number of people, cars, campers, and which sites I wanted, the system didn't allow for the individual families and couldn't comprehend the ratio of people and cars to the number of people allowed /site. I wasn't allowed to book it as a group over the phone either as we weren't doing organised tour activities, and was told to book the sites individually, or in groups of two families. Luckily for us, nobody booked the sites in between ours whilst I was filling in forms trying to book the other sites.
Also, not every site marked unavailable is necessarily unavailable. You can apparently fill in the booking details but not actually progress to the payment page, and the system will still hold your sites for 24hrs, marking them as unavailable on the booking calendar. I had filled in the details of which site I wanted and cars, people, etc... and my contact details, but got off the site before entering credit card details. I came back 5 mins later to start booking the sites again, but the original sites I had entered were now marked as unavailable. Not one other site had been booked, only the dates I'd put in. I thought it quite a coincidence, so I rang DERM to find out if it was my booking, even though I hadn't paid it, or if someone else happened to have booked the exact same sites. I was initially told when I rang, that neither they nor I could access the info to check if the sites were in my name, and that I would have to wait the 24hrs until they came off hold, and try to re-book them. I rang back the next day and spoke to somebody different, and they managed to find out that the sites were in my name, and allowed me to pay for them before the 24hrs had expired. A bit long winded, but if you really, really want a particular date and site, and it's marked unavailable, you may want to ring and double check if it's on hold or actually paid for.
