George, we've had a lot of discussions and some great pictures of various fixes, however the forum was hijacked last year and we lost all of the information. That's why you didn't find much when you searched.
I know that many have had doors that needed correcting so I'm not doubting that yours does as well. However, on my '89 Casita
, the only thing that it needed was a new gasket for the door. Apparently the bottom one had fallen off.
Rather than fix the door, Ches actually extended the floor out on his 13' Boler
to make a better door seal. Wish we still had that thread with photos.