If you haven't read this thread you, it might have some interesting information in it
http://www.skoolie.net/forum/viewtopic.php?t=14
I now have the engine battery, three deep cycles, and six of the high current ups batteries.
I no longer have a generator and can go a couple days without recharging, if I am going to use a microwave or other high current device I will run the engine while using it to help out the bank. I think you will really enjoy silent operation and the lack of setup once you get where your going.