If you're using treated ply, look out that the new ACQ treated PT, including the PT ply, is amazingly corrosive! I recommend you use double-hot-dipped galvy fasteners, or Stainless Steel ones, INCLUDING the angle brackets, etc.
Sometimes you can get by using a plastic spacer(s) between the wood and metal, heavy plastic sheet might be usable. Good attention to detail will halt galvanic action.
Good luck, and let us know how the asembly/wear is holding up!
The tool storage is nice, but where do I put the bed?