We solved this problem with a 12 foot porta-bote. We always ended up fishing from shore, but then heard about this foldable rowboat. It mounts right to the side of the travel trailer. Some people with good clearance (like 5th wheels) mount it underneath. It is only 4 inches wide when folded, so doesn't exceed legal trailer width limit. (Underneath the TT that wouldn't be a problem)
We unfold it, put a 40 lb thrust trolling motor on it and away we go! It weighs about 70 lbs. I can handle it myself if I have to, but the DW helps and it goes easier. About 15 minutes to put it together and you're off!
Here's a photo of it opened. (this one is just a photo I grabbed off the internet, don't know who these guys are)