I used to use the magnetic tow lights, but have switched to using the existing lights with diodes. It is so much more convenient and no risk of scratching the paint.
I have Progressive and found they are great to work with if you have a claim. We had a coach window replaced and then that window failed 1 year later (it came out of the frame). Progressive stood behind the original claim and had it replaced again ...
If you can find the hot and cold supply lines in an area where you can access them, install valves and fittings to blow the lines out with compressed air. You can then "winterize" the outside faucet/sink and use the rest of the trailer during times ...