Fowler,
The single most important think to never forget to use is YOUR BRAIN. By engaging this at the start, many problems can be avoided. I have towed many things that I would never advise being towed with the equipment I had, I did have some problems and all but a very few were unforeseeable mechanical issues. Then, there were the times that I was almost gotten by some other driver's mistake. But, to do this successfully, don't follow the vehicle in front of you. Be following the vehicle three or four in front of you.
Setting up a trailer brake controller is not a "Push-Here-Dummy" exercise. They are adjustable. learn what that adjustment does. If you have a friend that can be a native guide, take the advantage.
I do not know this rig, but if you add a transmission cooler, that can only cost you money and you only have to buy it once. Without knowing where you are an what you expect to be doing, I cannot tell you how essential it will be. Everything that I towed with that had an automatic transmission also had a temperature gauge for that.
Matt