RV door will not close tightly

Had the same problem in a 2004 Jamboree and it drove me crazy. Tried all sorts of peel and stick insulation and gaskets to no avail. Finally determined problem was due to the side wall curving inward almost 1/2 inch beginning near the door latch and up to the roof. The inner screen door made it impossible to add an additional latch near the top inside and I was afraid of a situation requiring a quick exit or someone needing to get inside in an emergency while occupied so I abandoned that idea. I noticed some RV manufacturers using a gas filled strut at the top outside of the door. The strut applies pressure in the same manner as the compartment door struts on my class A. It will also hold the door open. I found all the parts in auto parts stores and was ready to install them when I got the wild idea to up size to a class A. You can seek out one of these RVs and get some idea of how it works and if it can be adapted to your situation. Depending on how big the gap is bending the door frame may be a bit drastic. Just my humble opinion.