When we had our Popup we stored a shower curtain under the mattresses on each end. When it was raining or wet we cover the mattress with the shower curtain to give some protection, to the mattresses, while we were closing up. We would then open the trailer as soon as we could, when we got home or to our destination. Don't want any mold to grow.
2017 Forest River Surveyor 251rks
2013 Chevy Black Diamond Avalanche