As a shopping tools and especially if I am not sure what model, I find the interactive parts catalog is great for looking at details we can't see or won't remember!
https://catalog3d.winnebagoind.com/menu/Parts.htm
When you get close to one and want to look at things to avoid, you will have a bit of experience to let you know about some things to avoid! Also it can be great for sorting out details after you get it in hand!
Some of the things I look at might be as odd as looking at the tank sizes and that may be found in manuals but other things like how the dump valves are arranged and what they use to pull it can be a biggie on the smaller, more compact units.
One I try to avoid is the type which uses a cable like we see on lawnmower throttles? If they go in and turn to make a U-turn to pull the valve open rather than a straight pull, they tend to get bound up/rusty, etc or get loose to cause trouble.
I like a straight short pull!
Also I don't like RV that require a pump to let water drain from one waste tank to the other and then have a pump to pump it up and over to the drain. Extra gizmos often mean extra trouble!
It can also be handy to find those drains on a new RV if you have a picture of the water system! The manual may tell you to open a valve but not tell you exactly where to find that valve!
I takes a bit of playing with the system controls but the more you play, the less you have to work on things like crawling around to look. It lets you "look through walls" to see where things might freeze if too close to the outside?
Lots of links to lots of inof under the owners tab on the Winnebago home page:
https://www.winnebago.com/
Enjoy the trek of shopping! The more we know BEFORE means less trouble later!