We have a 2002 Viking pup that we used for the first two times recently. The first time we had nothing other than the mattress and it was bad. Target had a 1.5" memory foam on sale for our short king bunk for about $50. We bought and slept much better. It was raining when we packed up camp so I didn't have the time to test whether the top would close with it on the bunk, so we rolled up and will try at a later time. As for the sleep comfort, there was a huge increase in comfort. It's still not as good as home and might upgrade again in the future, but definitely would recommend.