My  bedding solution for the Roadtrek was to buy some mattress pad material, and a flannel sheet. Using the bed as a pattern, both pieces were cut to fit the bed.
The flannel sheet was then sewn to the mattress pad material, and elastic straps added to the corners.
This photo shows the mattress pad side, with the elastic straps.
I sleep on top of the flannel sheet with a light down comforter over me. For the colder nights I will use the Travasak, which is a little pricey, but a real pleasure to sleep in, and in my opinion, well worth the money.
The bed can be made up very quickley, which was the reason for this whole project.