You are going to love that Patriot! I would be most concerned about the holes in the bed. This metal is thin, and flat, where water can puddle.
I keep my bed covered when not towing. I use a Access roll up cover, that works very well.
It won't hurt the hitch to get wet, but I try to avoid it when I can. If I get caught towing in the rain, I hit the bolts in the bed with a little rust preventer, so it will run down through the bed holes.
I remove mine in winter.
Lube Plate is sufficient.
The pin box is going to hurt more than the bumper pull, but will only help you remember sooner.
Happy travels,
Jerry