Welcome, and best of luck with your search/selection. If we were buying new, 25FB/27FB would be among our first choices, for the nice usable queen bed in the front. We happened upon a great old Argosy with 2 twins, so for now we'll be content with sleeping across the aisle when we camp.
Unless your Expedition has the smallest engine or a low-numeric rear axle, I'm guessing a proper weight-distribution hitch and a good brake controller would allow you to safely tow a 25FB, but of course you're on a mountainous area and will face challenging towing terrain more often than us flatlanders.
Again, welcome!