We are going through some of the same thing. We are working on training them to remain on their small pads all the time the motorhome is in motion, and then we place the pads where they can reach them. Dogs can wander a bit, but when we tell them to get on their pillow, they are learning to mind those orders.
We were keeping the puppy in her kennel in the middle of the aisle. My wife likes it that way, but I think it's a royal pain in the arse. Kennel has to move each time we want to access the back for the rest room or food/water/beer. Just kidding on the beer. The pillow/pads idea seems to work somewhat. Although, the puppy loves to crawl back into the space behind my seat, which is about 15" wide between the back of my seat and the slide out wall. She seems to like it, so we'll be putting her pillow back there.
2006 Jayco Seneca 34SS
2006 Jeep Wrangler Unlimited Rubicon Toad