Shep,
Regarding that durn plate in the rear. First off, how old is your unit? Here's what I had to do with my plate. It originally came with what appeared to be two handles; one on either side and this would provide ease in pulling up on the plate to remove it. I also noticed that there were two steel angles welded on the plate, one on either side of the plate, well these angle guys were NOT allowing the plate to rest flush against the inner frame; so I literally cut off the angle brackets (To this day I have no clue as to what their purpose was). I then took the plate and lowered it down onto the inner frame, only to find out that the second grader that fabricated the frame did NOT square the frame in which this plate would lie. BUT....upon further investigation I discovered that if I took the plate and flipped it upside down, it would fit perfectly within the confines of the frame. So that's what I did and then I applied lots of silicone and it hasn't leaked yet...
Hope this makes sense. but KNOW this...you HAVE to get that bad boy SEALED all the way around...or you will leak water and this is NOT a good thing.
Lugnut