if you are not planning on driving it......
Take the batteries out and put them inside a place that stays at least 40 degrees.....its a good idea to put a charger on low on them once a month or so for a few hours......if the whole truck is going to be in a warm place just disconnect the battery cables....(if its gonna be in the garage) but still maintain the charge in them periodically
The only other thing i would really do is go down and fill it up all the way. The fuller the tank the less chance for condensation (water) to get in the tank and cause problems down the road....other than that it should be just fine......