Dry camping recommendations

If you have 2 12v batteries now I would just replace them with 2 6 v batteries to start with especially if you only want to dry camp for a few days. Once you start to dry camp more you will see what your energy needs really are and make simple changes to reduce your energy requirements. I use perked coffee on the propane stove, a Buddy heater for fall camping just to take the chill off, some battery operated lights and my 2 6 v batteries last 7 days before they need to be recharged. Your 12v batteries are probably the original batteries that came with the MH are probably not true deep cycle batteries. If original they are 5 years old now and if they run out as quickly as you described need to be replaced anyway. I had 2 12v batteries in my MH when I bought it and was surprised how much better the new 2 6v GC batteries were.