The board itself is pretty light actually. Even with the pedals and the lid it isn't that heavy. I didn't weigh it, but fully loaded and with the lid it is easily carried, even by my 100 lb wife.
I used 1/2" plywood and 1x material for everything except the angled runner, which is a 2x2 ripped down to 1 1/4". The way I built the lid, all of the weight on the top of it will be transferred via the 1x4 sides to the 1x2 rails on the outside of the pedal board. I am positive a cinder block dropped from say 15' on to the top would leave the pedals undamaged.
This shot may show what I mean a little better. The 1x4 sides of the lid sit directly on top of the 1x2 runners on the outside edge of the board. The plywood on the top of the lid is sitting on top of the 1x4 sides.
