You're only needing battery power for 3 days. How much power do you expect to use during that time?
The reason I ask is because I put in a group 31 AGM 12v house battery in my clipper. I have LED and florescent lighting in the RV which I use only as needed. I leave the water pump on all the time (it only runs when water pressure is needed - flushing toilet or running water). I may listen to music (using computer speakers plugged into the 12v) or charge the netbook and/or cell phone and/or kindle as needed. Everything else is on propane (fridge, water heater, stove/oven) - no microwave, toaster, hair dryers, etc. I use a Mr Heater Little Buddy for heat if needed.
I can go four days without putting a dent in my battery power. No charging required at all. So, depending on your usage, the right battery may be all you need. As you're used to tent camping, you might find this an easier solution than dealing with solar, generators, etc.