We recently purchased a 2014 Work and Play 28 FBW, which has creature comforts in the front (kitchen, bathroom, shower, etc.) but has a huge cargo area in the back.
It's perfect for race weekends and camping trips too!
Of course, being engineers, we couldn't help but immediately start modifying it!
Tired of packing and unpacking tools, the first mod was a tool box. I noticed that there was about 20" between the edge of the kitchen counter and the fold-up sofa, so went to Harbor Freight to shop. Most of their standard tool chests are 24" or wider, but there was an "add-on" box that is meant to attach to a larger tool chest. 18" wide, so it was perfect!
We also have a quiet little air compressor that fits in the same footprint, so I welded up a steel frame to bolt to the box and floor, and leaves room for the compressor.
The frame bolts through the floor (1" FRP in the work and play) and bolts through the sides of the bottom of the tool box. There's even a lock in the box to keep the drawers from coming out when travelling.