A dually truck will help with it not being so tippsy, but with big tires, lift, camper and trailer, don't expect any sort of fuel mileage out of it. I have a friend with a simular set up, he lowered the lift btu kept with the bigger tires and he isnly getting 12-14mpg. H wish he would have stayied stock with it, but oh, well.
Look for a camper that is not so top heavy. Lance are great campers but are very top heavy.