I am a fat man.Fluffy.Many can attest to this..And I sleep like a baby in my 36" mattress, behind the seats,on my side, but always end up waking up in some strange position.I sleep better in the van than at home, go figure.There is a permanent bulkhead between the sleeper and 8 ft cargo area, with a flatscreen and a dvd player mounted to it.It works for me, surprisingly.Absolutely no problem staying warm or cool this way.In the summer, I will sleep with the side doors open in a good area, except when I know OVM is around, he woke me up by tickling my feet once...lol.What a way to wake up!! lol.