OP, sounds like you're set up pretty good if you're only 600 pounds over. My '05 Chevy dually is rated for 11,400. With just the camper and the family I'm about 13,100. If I hitch up my boat I'm about 13,500 on the truck. I'm not over my tire weights or the rating of the axles. I've logged thousands of trouble free miles with the cruise control set on the speed limit.