I have 2 cents worth....
- Battery boxes come in many types. You can attach the box to the tongue or a tongue rail straddle kit. It's usually a good idea to drill drain holes in the bottom of the box
- Desperate people steal batteries - and the easy mark gets stolen first. If you store your TT in a high risk area....Tape a sign on it that says "shorted out"
- Always disconnect your battery for storage. Install a switch, quick disconnect, or pull the fuse.
- Assuming you have a Norcold 3-way Fridge (propane, 120V, 12VDC) there should be an "Off" setting for the selector.
- Connecting to shore power should recharge your battery - but since your battery was not dealer installed - you should refer to your owners manual for wire identification and any further steps that may be required to route charging voltage to the battery connections.