^ Basically exactly what he said!
Emphasis on don't turn on the water heater until it's full of water.
It will be switched, not auto on all the time just because it has gas or power. It's electric ignition, not a pilot light you have to light like a residential water heater.
Fridge is even simpler. Turn it on and go through the modes. It will prioritize in auto mode AC, LP, DC in that order if that source is available. Can't screw it up. Worst case you have no propane and no AC power plugged in and it runs on DC until the batteries die.
The one thing I would be cautious of, is that there are things that don't work or leak that are not discovered until after you take "delivery". As your knowledge is limited and warranty work will be difficult due to the long distance delivery, do what you can to have some ammunition for repairs (IE refuse delivery if everything doesn't work and have that in writing before joe schmoe drops it in your driveway and takes off.)
Can tell, you're apprehensive about your new toy and this should not be a stressful deal. It's fun, don't get too wound up about it. There's a great chance that everything works just fine. If not, there are many (not just us on this website) that can help or walk you through minor issues or fixes.
Can you be well read on the owners manual before receiving it? That way checking the simple operations of the mechanical stuff can be done efficiently? ( I picture making the delivery driver wait before you accept it, based on running the systems, which will be difficult unless you get it sorted before hand.)
