Cover for entry step well

[CherieE]

I'm starting the mods for my new-to-me 2015 Precept 29UM with an easy one - a lid to put over the step well when the door is closed so I don't break my neck falling into it at some point or the dogs don't end up tumbling down there while they are playing. Easy-peasy slab of sanded wood, either stained or covered in carpet, with a couple of handles.

But ...

Has anyone installed one in their RV with a piano hinge along one edge so it's easy to tip in and out of place, and hook out of the way when needed? Anyone know what I'd be drilling into if I attempt this? Just the subflooring from what I can tell, but I want to be sure.

In the 29UM, it would be perfect to put a hinge along the left side and let it hook/rest on the kitchen cabinet. There are just about 3 inches between the edge of the step well and the cabinet.