To some extent, it depends on how you view the TD. We think of it as a metal tent, not a miniature RV. Consequently, Biffy Bags, rather than a portable toilet, are enough for us when required, and they store small. We keep the rain gear, as well as all other emergency gear, in the tow vehicle (it is our "back-pack"), and one down comforter is enough in the TD, even in winter. Think down sleeping bag. Etc. We have never lacked for storage even without the under mattress storage capability.