I ran a similar (albeit not nearly as cool and I'm loving your build) kitchen box on a 10,000 mile roadtrip in September which included coast to coast on the TransAmerica Trail and beat the be-jezus out of everything with not so much as a loose board on the kitchen box. Mine was 3/4 ply with wood screws. The next go-round will have more 1/2" ply and I like the hole saw idea do cut weight, also love that top slide, mine was stationary. The space behind where you have the drawers is where I built in my house battery.