I don't intend to digress, but will the camper be on the truck or detached and sitting on jacks/supports? If it is detached, you should look at skirting (www.rvskirting.com is the first on the list.)
I'm looking into this for the relatively mild Texas winters because the skirting (which is staked down to the ground) breaks the wind and creates dead air space under the bed where you need it most. If electricity is available, adding a 100 watt light bulb or a small heater would also help in keeping that area warm so the bed isn't as cold.