I have never heard of anyway swapping in a 6-spd trans into your generation truck. The design of the vehicles have electronic modules that communicate with each other, in this case transmission and engine as well as stability control. I do not know if they would work together.
At 230k miles, any number of things can go wrong. Heck, at 1000 miles anything can go wrong while traveling/towing. Prepare accordingly. My advice, save your trans fund money. Carry cash or a credit card for when problems arise. Hotel, towing, service, etc.