Few thoughts:
1. Converting the couch every night - no big deal. Converting the dinette every night - pain. Night time will come and you will always have to move things off the dinette. The tables are a pain to deal with - not difficult, just a pain. Cushions never fit easily.
2. You won't be able to sit in your recliners and talk into the late night with the kids sleeping right there on the couch and dinette.
3. At their ages, will the kids prefer to be in a tent with their air mattresses? Heck, you could build a lean-to for them, or even a tree house and they'd love sleeping there far more than in the trailer. Look outside the box for sleeping arrangements for them since it will be a stationary camp on property you own.
4. Personally, I never liked the bunks - even as a kid. I always felt claustrophobic in them. And the "private space" really isn't private. Also, when boys start growing, they GROW. You'll need to make sure you get a bunkhouse that will fit them in 4 years when that happens.
