Don't do it! It's just that simple.
I can't imagine a half ton towing at least 5000 lbs of truck and trailer. And then add on another 1000 lbs... (loaded with food and water and gear) We are all missing other things besides braking and whether your state allows it! There's also, suspension, axles, tongue weight, cooling, and let's not forget tranny/clutch!!
A little imagination is a good thing,if you can make it a reality. At least that is what I told myself when I started building my toyota, mabye I should have just bought a jeep and a bolt on lift. Keeping the tranny cool is probably the only other problem I havent addressed, I need a good aftermarket cooler. the rest that you mentioned is verry well uner control.