A couple of things here. First of all, since you know what unit you want, you could probably find one using the internet, also run from this dealer.
Next, what would plugging it in a day ahead accomplish? Two things I can think of only, refrig works and putting water in the tank would show that system working. Anything else? Furnace you can check out by turning it on when you get there, also lights, converter, battery, oven, propane, air cond. . I only mention this for your next RV you look at.
A number of dealers do not check out the systems on their lot as they might just sell it to another dealer. This dealer appears to be one of them.
