Lots of good ideas here. What I did: got 2 driveway markers( like this:
https://images11.palcdn.com/hlr-system/Thumbnails/42/420/4200/4200187.jpg
which are a round red reflector on about a 3 foot rod. Found some vinyl tube the rod would fit in snugly, hose clamped the tube to back of boat trailer. Slide the driveway marker in all the way so reflector is snug to trailer while traveling, pulled out marker so I could see the reflector in the mirrors at the boat launch. Worked great and got lots of positive comments from other boaters and RV'ers.
That was with my TC. Now I have a Class C and use a Rear View Safety (Costco) camera with a 7 in monitor that I wired to be on all the time so I can see back there while driving. Works great.
