To me everything looks fine except here:
Putting a roller at this location should stop the damage, now how you do it is a different animal.
Being you got an aluminum trailer, it would be prudent to continue the theme. Most likely in order to support the bow without redoing the whole trailer you may need some help from someone that can fabricate a bracket in order to bolt it to the beam near that location.
A 12" roller with 5/8" rod should work (if you have the room) bolted to the rear or front of the problem area and leaving the centering posts.
Being you got tandem, you should be able to pull the boat back (with the truck attached) by tieing to a tree or pushing with a strong back (son in laws), just far enough to clear the work area. If the weight is balanced or heavy on the tongue you can disconnect it or support the transom in order to disconnect from the truck to perform repairs.