Ron,
You're right regarding foam mattress toppers.
Foam toppers vary A LOT in not only thickness, but material stiffness/density, and heat dissipation. I think it might be big business out there to manufacture/offer furniture foams with several parameters that are variable. The DW had to find a foam that played just right with the (excellent, BTW) stock under-lying Winnebago mattress. Now she finds - for her back - the Class C corner bed's feel to be superior to that of our $$$$ stick-house MB king size mattress.
But once found - and when combined with a fitted foam topper sheet/cover - our small Class C corner bed is a winner ... especially in comparison to what other (negative) things one has to put up with in a longer Class C.
