Most important disregard, "well everything worked last time out."
It's usually pretty easy to determine how well it's been maintained, spray some water on the skin, see if it's been waxed/sealed recently.
Go thru the obvious, ext lights, batteries, furnace, water pump, electric jack, shore power cord, water heater, co/smoke detector, fridge. Int. lights and fixtures, plug in check converter. Inspect door, windows and roof vents for leaks, esp black tank vent. Plastic cabinet latches and pantry slide. Tires, brakes & axles.
Look for filiform.....aluMATTER*|*Aluminium*|*Forms of Corrosion*|*Filliform Corrosion
Good luck keep us posted.