Sorry, TMI, but here goes. My number one concern was a bathroom size and layout I could actually use. I'm a big guy and it had to be big enough for me to be able to sit without having my knees forced together and sit with my arms crossed. I wanted to be able to reach to wipe my butt, not scrunch my face into a wall when I bent over to wipe or contorting myself and falling face first into the floor when trying to wipe. My older trailer required me to step one foot into the tub when wiping. Some trailer I looked at I would look at some of the amenities and features, but every trailer I entered I would go straight to the toilet, close the door and sit on the throne. Many I walked straight out of and on to the next one after only checking out the bathroom.
The second was a big enough shower to stand upright in and not feel like the walls were going to close in on me and I could actually bend my knees to reach and wash my feet.
Third was waste and FW tank sizes.
Fourth it had to sleep 4 without using the dinette.
Fifth was cabinet storage space.