Regarding the patch on the roof? 16x16 inches sounds about the size of a vent. What is on the inside of coach, on the ceiling, at that same spot? If the ceiling has some kind of patch there on the inside, I'd almost bet it was a vent that was removed. If there is nothing on the ceiling, all one solid ceiling with no patch 16x16 inches, then more than likely the roof had a tear. I imagine the roof is a rubber roof, and then, this would be a simple rubber patch over the tear.
I suggest you get up on the roof and examine it more close, push around (or stand lightly) on the spot and see how solid it is. Examine the seam carefully and reseal it if it appears to be cracking.
And FYI, don't feel bad or feel you should have buyer's remorse. Even seasoned "experts" will buy brand new RV, just to find multiple unwanted "surprises" after they take delivery.
Focus on what is good about your camper, and just fix the items that need attention, one at time.
And talking about "fixing" .... um ... welcome to your new occupation, "Jack-of-all-trades" because going forward, as long as you own your camper, you will always be fixing something on it! You'll get pretty good a carpentry, electrical, and plumbing! Be grateful you have a good head and are willing to tackle things yourself. You'll save yourself a lot of money on shop fees.
