I forgot our bottle jack on a trip and had to use the TVs jack. Turned out it worked much better, faster and with a long enough handle that my wife was able to jack the trailer up easily without having any part of her body underneath the RV. I had checked the spare and made sure it was good but there on the side of the highway I learned the stud was too long to allow the star wrench I had bought to work the nut on the spare. Luckily I travel with an 18v drill, light and sawzall with wood and metal blades so I was able to cut down the stud.
As far as the batteries where and how are you planning on camping? Most, not all but most campgrounds with hookups are more or less parking lots. And expensive parking lots at that so for me I'd rather go somewhere where we don't need the AC like up in the mountains and just use the 12volt systems. If you plan on going to AZ or somewhere really warm you will need hookups for the AC but if you stick to the more temperate climates the money could better be spent on a solar panel than a new converter.