We have spent the past year in a 24' travel trailer, and encountered a variety of problems along the way, so I have picked up a pretty good bit of experience working on these things.
So we came across a '14 Montana, already parked in a beautiful spot, 125 gallon propane bottle hooked up and a small wooden patio with steps.
Found a long-standing leak at the panel where the dump valve handles are located, and had to put a dehumidifier on that area to dry it out.
Appears the previous full-time owners did not flush out the black tank, so I have a mess there that I am slowly chipping away at.
I am not sure if the black valve is opening all the way (reason I came to this Forum, in the first place!).
Since I am using the black tank flush, I found that the anti-siphon tube under the bedroom sink leaks when using the flush, so in the process of bypassing that thing. Happened in my other trailer, as well.
Probably my biggest gripe is one of my recliners is literally falling apart underneath us. I have had to take the crossbar out that holds the seat springs, and reposition it twice, this time with a healthy dollop of gorilla glue, so hopefully it holds this time. Every time it lets loose, it grinds of more of the wood on each end where it attaches, and soon I will have no more wood to work with.
So, lots of little gripes, but overall we LOVE the place!!!
I am just so happy that I can do this stuff myself and don't have to hire help!