20-28' range... Any specific reason you want to stay in this size range? I will give you one reason and that is the older National Parks and other government run campgrounds that were built long ago for smaller RV lengths. For example The Navajo National Monument has a 28' max length. This is from the RV's bumper to tip of the hitch NOT interior size. North Rim Grand Canyon is a popular spot with reservations months out. Although 40' spots are available (fill up fast) the smaller spots 27' on down are open more often to reserve. IMO the largest RV for these old campgrounds is 27' and roughly a 25' interior. Sure with skill you can go larger in these small parks, but, that becomes work not fun. Trying to stay an extra day with the campground host looking at the only open spot to do so and it's too small for your rig ... been there and didn't stay another day.
The smaller the RV in length the more spots are open. It is difficult to keep the size down on a RV and check all the boxes. There are a few small campgrounds that 27' is simply too big for. Going from tent camping to an RV should be easier to stay small and be able to reach those smaller less popular campgrounds.
You can always upgrade your RV size later as the larger RV's are more common in the for sale ads IMO. Small RV's are not so common.
You can rip out the RV Queen and put a full size queen in if they left you the room to do so. Measure before you buy.
I do own an Arctic Fox 27-5L 5th wheel that is 27'. Later years Northwoods MFG made wider and longer. Last year I had a $700 repair to a common flex crack and ddelamination below the bedroom slide. Thus the "dissolves in water" sides they put on all RV's is my only gripe and affects all but the shiny metal tin cans, aluminum siding (making a comeback in new RV trailers BTW), or fiberglass RV's. Fiberglass like: Scamp, Bigfoot, Casita.
If you see any blisters, bubbles, or wavy outside walls it has delamination. Expensive to have fixed and hurts the value. Resale value = scrap depending on how bad it is. Don't walk: RUN away!
With deep discounts offered you may look into a "new" RV esp in the smaller size. Be warned the build quality of some of them is downright disgusting. We have blown the roof clean off a couple new RV's while delivering them to the dealer. Some ARE built better than others even with the same name on the appliances in them.