Your personal needs will dictate what equipment you will want to consider as optional power sources. At some campgrounds the use of generators is restricted. Check the costs involved in the purchase, maintenance, and repair of supplemental power equipment. It seems that very few purchasers of recreational vehicles buy them in the dark of night. Check all of the lighting sources.
Storage space is a very personal thing.
However, it's important to remember that the way you use your RV may change over the time that you own the vehicle, so anticipate the future as best you can. Check if there's adequate closet space to hang clothing. Once again, you might want to make a list in advance of things you think you'll want to take and check the storage against the list. Find out about the hitches that are available. The towing issue is a critical one that is surrounded by some degree of controversy.