The beauty of 'covering' an old access is a patch of the same aluminum can be placed over the old opening and riveted in place.....and it
( the 'patch') will appear perfectly normal. You will need to locate the same aluminum used for your coach and if there is no way to buck the rivets you can use olympic rivets. I shall leave those details to other members who surely will be posting to your question.
Neil and Lynn Holman
Kirk Creek, Big Sur, Ca. coast.
1966 Trade Wind
1971 Buick Centurion convertible
1969 Oldsmobile Ninety Eight