This style camper hatch may put you in trouble for rot:

There's a shield above the top hinge....

....the shield thing: I recall that aluminum doors on RVs and homes (many years ago) had a neat little shield that cups the top of door frame. Hmmmm? This could work for our propane door providing an appropriate width is available....

I've got to check out for a while....will be back at this Forum tomorrow. Thanks for all the ideas.