Flush the black and grey tanks REALLY REALLY well. You might want to fill the tanks with water after flushing a couple of times and then add a gallon or so of bleach in each tank and let it sit for a week or more. Go online and locate the instructions on how to install your brand of toilet. Then work backwards thru the instructions. If a Thetford like ours, you will need a LONG extension to loosen the nuts on the bolts. And a tight fitting socket on the end (tight fitting to the extension). I would suggest you use an under counter fridge on an inverter(we have one similar to this 4.4 cf fridge http://www.homedepot.com/Appliances-...atalogId=10053
and have to buy another one as it's our food cart's fridge PLUS we have a 12 cf Freezer to install). Those RV LP fridges are dangerous. They catch on fire. Shame about the water heater. If it had been gas, you could have simply installed an electric "Hott Rod" to take advantage of the electric that is included in site rental. Perhaps you could sell it. But before you do, better price new replacement. RV water heaters are pricey. It's why we decided on a tankless water heater for the bus (this is what we want http://www.amazon.com/Eccotemp-FVI-1...=1QZPZW5234PI8
).RV ovens are notoriously bad at cooking, so acquire either a pizza stone or unglazed clay tiles to line the tray above the flame (I used 4 quarry tiles in the Class C's oven). You will need to keep the rubber boot on the toilet flange to reuse.
Trailer/campers/RVs tend to be built from the floor frame up. Everything sits on the floor and the roof sits on the cabinets. Be careful removing stuff.