While I'm at it--
Here's my solution for a snug, comfy upper bunk
that's free of annoying gaps in the mattress.

Get a natural fleece mattress pad, half inch thick.
Cut it to fit the bunk, allowing extra length on the ends.
Attach velcro at head & foot to secure mattress pad
to mattress & keep it from shifting.

Fleese pads add a lot of sleeping comfort, & are good
in all weather--hot & cold--& seldom needs washing
if covered with a cotton bottom sheet.

Mine's been washed repeatedly in my travels, usually
in a five gallon bucket with cold water & Woolite.
It dries quickly & is back on the bunk in no time.
It stays in place nicely & gets folded away, in place,
when the bunk's folded up.

Phaedra
'85 Westy Basecamp