Most important 5th. Wheel features for full timers

All the previous posts are spot on. The one thing I will add is, what can you get to with the slides closed? We like to pull over and be able to get to the fridge for lunch or that quickie bathroom break.

Another thing to look at is what utilities are in a slide? With fulltiming, you're going to be moving the slides a lot. If your fridge or even the whole kitchen is in a slide, then all those connections (sewer, water lines, gas lines) are going to get a lot of wear and tear.