make sure you do all the above including sitting on the toilet, brushing your teeth, using the stove, access to stuff while slides are in and out, check out storage for adequate space for your supplies, chairs, grills etc. So act like you are in it and useing it, besides all the stuff we look for operational as of course these are important, don't forget the usability of the unit as well. We purchase one a year ago and over looked some stuff, long story short, we sucked it up and traded with loss of course and then bought what we really wanted. Floor plan is important as well and done't forget about holding and water tanks as to how you will use it. back bumper strong enought for generator or modifications etc, etc, etc. Good Luck & Be Safe ! ! !