I got a 3 inch high memory foam topper from Costco and the Froli travel model installed last night and it is a night and day difference in comfort the top closes fine. If you’re Alaskan mattress is no higher than 4.5 inches that combo should work. We’re headed out to the boonies for some cold camping in NM tonight so I’ll report how it does but it should be great.With regards to the Froli system for an Alaskan camper. I have a cab over(almost queen size mattress) flat bed Alaskan and there is not much room for any added height. But, I tried the travel Froli last week which is the shortest system. Although it made our Alaskan mattress pad feel much better, the sides would not fold down. It bound the hinges. I talked with Nick Atlantic( Froli dealer ) and they were great to work with and very amiable to return/refund the system. Our mattress doesn't get wet either, with the winter/wet weather camping.
We are getting ready for a 4 month adventure and tweaking out the gear and trying to make the mattress a bit more comfortable. I think a possible solution for the AK pad might be to have a thinner mattress made. Maybe a 1" memory foam or good thinner mattress and the Froli 1 1/8"under that). Could be the perfect set up. But I really like the quality wrap on the AK mattresses, which are a bit firm, hmm could be another suggestion for the AK camp design.