I'm thinking, mount a bearclaw latch to the lid, placed in the void formed by the rungs on the ladder. On the platform side, place the strike on an "L" bracket in the base of the ladder recess. Fabricate a filler plate to fill the access hole on the rear of ladder door, and attach that to the actuator rod on the bear claw latch. Completely smooth, just press the button to open, and close like you would a car door.

i think one or two magnets would be a sweet idea would look good too plain jane and two angle brackets underneath to lock it just get the brackets powder coated so it wont rust

I took the foam out between the ladder and the lid so now it sits down flush but I will put some softer foam in there , I wonder if I put another gas strut in there so there is 2 if it will hold it down snug enough . With the factory latches when sitting and idling they danced and rattled liked crazy .