All the "kits" I've seen are generally over priced with sub par quality components. I would try to use "full size" 60 cell solar panels which are about 40" wide by 66" long. They are about 300 to 350 watts each and should cost around $.60 per watt.
Magnum or Outback would be my first choices for inverter/charger. I wouldn't mess with stand alone inverter, get an inverter/charger which will also have a built in transfer switch. It makes the wiring much easier. Some will say that now you have a common failure point which is true but these devices are incredibly reliable.
Purse sine wave for sure. Buying a modified sine inverter is like buying a black and white TV.
Running electric heat in an RV with solar panel is just an exercise in futility. Forget about it.