For whatever it might be worth ....
We didn't want to deal with any sort of mattress topper.
Rolling it up and storing it, especially in a Scamp13 was
a royal pain in the tail.
In our previous Scamp13, I replaced the foam in the
bed/dinette cushions and in the front sofa cushion
with a better quality (more resilient medium density N36)
regular foam (non memory foam).
That made sleeping much better but, I found that sitting
with all your weight
concentrated in the smaller area of
your rear end tended to allow us to sink deeper into the
cushion(s) that I really wanted.
All single foam density cushions that have to do double
duty as both a bed cushion and a seat cushion seem to
be a bit of a compromise.
With our new Scamp16D-A trailer, I replaced the factory
foam with a 3-layer foam sandwich. I had our local shop,
that does upholstery foam, glue one inch of medium-high
density (i.e. N36 sleeping foam) to the top and bottom of
2 inches of higher density N44 foam (i.e. sitting foam).
The result so far seems to be a cushion with good firm
support but a more resilient "pillow top" for a bit more
comfortable sleeping. Since making the change, we have
only been out a few times but, so far, we are happy with
I know that different folks have different firmness wants
and/or needs. The type and thickness of the foam in each
layer can probably be adjusted to suit individual preferences.
Our foam sandwiches consist of 1" of N36 foam on the top
and bottom of 2" of N44 foam. That makes the new cushions
reversible and, so far, still seems to provide excellent support.
No topper of any sort required!
The total cost of building the foam sandwiches, removing
our older/harder foam from the covers, and cutting and
re-stuffing the new foam back into the covers was just
about $220. Although not terribly cheap, that seemed
reasonable to us in comparison to purchasing and storing
some sort of a mattress topper.
I will attach a couple of pix of the 3-layer foam sandwich.
I know it may not be a solution for everyone, but I will
just pass on our solution for whatever anyone thinks
that it might be worth. Of course, as always, YMMV.
Safe and happy camping to all!