Don't know you or your physical condition but consider this....TC's are the hardest RV to enter and exit, something you do multiple times per day. When you look at a dealer's or an RV show they are set up so there is only a step or maybe two from the ground to get in...this is not reality once they are on a truck. So find someone with a camper on their truck and climb in and out and envision how many times you are going to be doing it and in less than ideal conditions. Then go try a B+ and a B and see if a TC is really the way you want to go. At 75 it's not going to get easier.
You will be able to improve handling and perhaps even improve payload up to your rear axle capacity, there's lots of info on here. But hauling heavy does stress your truck more than hauling light...I'm saying you will shorten the life of your truck to one extent or another. No way around that one.