We added a 2" topper to our mattress in our old Crossroads. Was disappointed in the mattress in the Coachmen. So we just swapped the mattresses.
We can still lift our mattress. Just remember that it adds some more weight and if you have the hydraulics (we don't) they may not be able to support it and you may need to upgrade.
2016 Coachmen Freedom Express Liberty Edition 292BHDS