The above advice appears to be very good...I'll confirm the Stabiloads for sure on the Dodge as the overload springs on mine are now engaged. When looking at new trucks check for the overload springs and how they work. My Dodge sits tail high empty and level loaded...not sure about Ford and GM. Longbed dually is good but some folks are SRW and do just fine with heavy loads. The other thing to consider is the tires and wheels when looking at load. READ this thread: put my 19.5s on today...full of info and discussion which will give you room for thought.
NOW when it come to tiedowns...I am a strong advocate of the purpose built systems that have tension systems and such. The old chain and turnbuckle system can destroy your TC...here's a little of why. The chain is not a shock absorber and when the TC and bed move together and the chain is attached to the frame the chain will not extend when pulled, something has to give and it is the TC attachment point not the frame. And conversly when it rocks to the slack postion and snaps back...ask yourself what was the strain on the TC when it pulled tight. Also tiedowns are just there to keep the TC from moving around not really hold the TC on if you turn over or something...yet there are many images of TC still attached to the truck even after a crash..usually a side or something is badly damaged. Somewhere I read a paper on the physics of tie-downs and the angles they should be at..very interesting. That was ages ago. But there are things you can do to help your camper stay in place, you'll find those here as well...I use a spray in bedliner with a heavy rubber fitted bed pad...After 10 of 1000's of miles mine shows some wear and it is a good inexpensive investment. Good knowledgable dealers will have worthwhile suggestions and products available to get you all set up. If they don't have a clue what you are talking about drive away...they will not be good after purchase service. Above all if you have a question ask it here and then go back and find out what the sales folks say...it is a good test and makes them think you are in the know and can't hoodwink you. But after so many TT and 5er's I bet you got that part down! Welcome to the TC world.