The wife and girls (now 5 & 9) have been to both CM '07 and CM '08. They like it so much that we are pulling them out of school to attend this year (in the past they were "off track"). We have a popup camper that we drag out to stay in. I'd suggest either getting a couple tent sites together or renting a RV site to pitch the tent in for more room. I wouldn't get a "cabin" if there are still any available because they are small for a family IMO. There is a playground at the campground and a pool. Unless it is really warm though I'd stay away from the pool
If the wife and kids like sightseeing there is plenty of that to do as well as riding bikes.