Since you're heading back tomorrow...may I suggest that before you do anything else...your hubby puts a volt meter on the battery terminals and read the voltage. Anything less than 12.0V should be cause for concern and confirmation that you have a significant drain on your battery even with the trailer disconnect switch engaged.
Once you know your starting voltage point...you can plug in the camper and check all the other stuff that has been discussed above.
BTW many folks don't have an clamp meter in their toolbox and it is a very useful thing to have around to check all things electrical...AC &DC on the RV and at home. Here's a nice inexpensive one from Amazon which comes complete with instructions (in English - LOL) http://www.amazon.com/Uni-T-UT204-Au...mp+clamp+meter