My door was very hard to close. The latch plate on the frame looked like it was cut as tight as possible, hence no adjustment could be done. However there is a slight curve in the frame, so I was able to file the curve of the frame and moved it out 1/16". The door now shuts just fine. I still need to close firmly, but it is acceptable. I also had to file the top screw hole a bit in order to use the existing screw hole.
Side note: The CARMTEK 10 digit RV Door lock fits the door I have. Now I have a unique and sturdier key with Key Fob's.