I would prefer it not to be boxed so the components are that much more accessible and it would also give you a better visual indicator if you started to leak somewhere. The box does keep the UV rays off their PVC block and manifold which would keep them from becoming sun bleached. But I would just mount the assembly to 1/4" or 3/8" ABS sheet, they sell it in various thicknesses and precut sizes, it’s also relatively inexpensive. You could even bolt up some steel to the bottom kind of like they did at Chipotle
so you could lean it back and mount it to a truck bed rail or the edge of a flatbed.