There are a variety of checklists available online, some more extensive than others. Do some Googling and choose one you like. There are a couple of things that come to mind:
Read the owner's manual cover-to-cover before your pick-up, that way you'll know what questions to ask. It's available online here:
https://winnebagoind.com/resources/m...anuals2019.php
Make sure they explain the electrical systems (both 12V and 120V), showing you where all the circuit breakers, cut-off switches, GFCIs, etc. are located. You'd be surprised how many people post questions about these on rigs they've owned for a while. The same goes for the water system, refrigerator, A/C, heater, etc.
On your overnight run everything, even if you don't need it. When you run your A/C and heater make sure you run each long enough to respond to the thermostat.
You didn't say if you have any prior RV'g experience, which is a big variable. In any case, have them show you the correct way to hook it up for towing.