if you have the room, dump the 12 volt batteries and get 2 6 volt golf cart batteries instead. You still wire it up for 12v (two 6's in series), but you get almost twice the amp/hour rating of two 12v batteries in parallel.
Or just get one of those honda super quiet gensets and let it run a few hours a day to keep your 12v bats charged.
When I camp in the sand at coos bay, I can usually get an entire week out of my batteries, and a 7 gal propane tank, and thats even with running the furnace (although, very sparingly).
Make sure to wire it so your truck bats are separate from your camper bats unless the truck is running. You can make your own combiner from an extra starter relay and wire the big posts to each battery, and the small trigger post to an ignition hot wire. Charges your bats when the truck is running, and separates them when the truck is off.
Plus one on the good ground, especially if you have a good charging wire.
Loading and unloading suck, unless you have electric camper jacks, and even then, its still annoying.
Keep it stored out of the weather if at ALL possible. The caulking they use on the roof to seal everything will last alot longer, and you will have less chance of a leak. Also, when its not going to be used for a long time, open all the cupboards and flip the cushions up and put a small electric dehumidifier in it. West Marine sells one that looks like a giant pancake. Puts out just a little bit of heat, and moves the air around. Makes a big difference.
Learn how to winterize it now, and be prepared to do it in a hurry when you realize in october and they are talking about that first freeze, that you havnt done it yet. Couple jugs of pink RV antifreeze in all the sink drains, down the toilet, and either air pressure your sink lines clear, or pour more pink into your drinking tank and run the sinks until the water tastes sweet. Then leave the faucets all open, and the pump off. (The pink stuff is non toxic, but your still not supposed to drink it. Flush your system in the spring).