220V Camper system advice?

[carbonspork]

Hello,

I have an 220EU external AC plug on my van. It powers (from what I can tell) nothing but the refrigerator and the heater system. My van has the under driver-seat mounted battery, which was removed after an electrical fire apparently quite some time ago. I replaced the battery and redid all of the wiring and there is a relay that disconnects the house battery from the starter battery when the alternator is not running which I assume is so you don't drain the starter when you're running your 12V camper accessories.

Anyway, I got everything functioning from a 12V house battery now, which is currently not connected to the alternator charging system. My first question is - is the relay sufficiently safe enough without a disconnect solenoid to hook up the alternator to the house battery? This is a basic car battery, not a deep cycle marine one, which I know if totally draining is a better option.

My second question, is what is the most reasonably priced way to be able to run the 12V camper system (and charge it ideally) from the external power hookup? Nearly every campsite here has 220 hookups. Is there a charger or regulator that people would recommend for these (I have a hard wire 220 in that compartment also)? I am powering the following inside:

The Fridge
The water pump
A couple lights
We likely will never use the furnace so I haven't bothered with it yet, but in theory I'd like it to work. (it's very temperate in southern Iceland)
At some point probably a USB charger for phones.

If I've explained anything wrong or asked the wrong question, please correct me - I'm new to working with camper/house battery setups.