Matt - with the security of batteries becoming a issue these days you might want to consider doing somthing like this.
photo from google images...
This is a 48-inch metal truck bed side mount diamondplated tool box. This is just the perfect size for four each GC2s Golf Cart 6V batteries... Even just using two of these powerful batteries and the rest of the room for some outside tools is great as well.
If you have room on your tongue for one of the batteries then you can use this idea for a larger metal box going on the top of the tongue and extending over the edges.... Some trailer have the battery first on the tongue and the propane tanks next to the trailer wall. these are not impossible to move so you can have the battery box next to the trailer front wall.
This box is lockable and can house all of your battery switches and fuse blocks. You can gain access to the inside of the front storage compart by going thru the front wall with a PVC electrical junction box on both sides of the wall with a large hole drilled between them. These seal up great for weather and bugs. It looks very nice as well...
Something to consider. I have found you really need something close to 300AH if you want to successfully do some camping off the power gris and use an Inverter as well.
be glad to share info with you off line if you like via emails where I can send some better photos.