My boat is 18' as well, but it weighs in at about 3800lbs. Not sure which direction that I want to go with a camper yet, but it probably won't be as big as what you've got (or had).
How did you have the hitch setup on the camper?
A Reece Reciever Hitch.. welded to the 5r, main frame rails.. independant of any OEM crossmembers.