I'm planning on purchasing a used Class B early next year and taking a few leisurely months traveling around the US. I'm retired, older than dirt, and have a short "bucket list" mainly golf, bowling ...
Some of those models are based on the diesel platform. In any case, they will all make it over the mountain, and in the end, the one you find that has been well cared for and has had regular roof cleanings and recaulkings and it has been lightly used but enjoyed by caring owners will be the one you select.