There is a poll here that asks about bedding. Most seem to use traditional sheets and blankets, a few use the RV specific Travasaks and others use sleeping bags. We opted for the sleeping bags. We started out with our tent camping bags we had for years. They were heavy duty Coleman 5 lb. Holofil 42" x 81" sleeping bags. They were big and bulky and got in the way. We make up our bed every morning and roll up the bags and put the electric sofa up as we think the B is too small as it is for when we are up and about.
So we bought two new sleeping bags at Costco. This past spring it was the only bag they sold. The model was the Coleman Issaquah. The details are here at Amazon.com...
However, we paid $30 at Costco. Briefly they are 36" x 80" and have a zip out flannel liner that can be cleaned separately from the bag. They come with a stuff bag so can be put away compactly around 12" in diameter by about 16-18" long. They can be zipped together as one large bag. Side by side they fit in our Pleasure-Way Plateau electric sofa bed almost exactly. When stuffed they can be used as bolsters.
Here they are open for sleeping and then put away in stuff bags.
We use the sofa pillows under our bed pillow to bolster us when watching TV or reading a book. When the sofa is up I'll use the sleeping bag stuffed as a bolster under my arm.