i used a 3/4" heater hose, long enough to loop back onto the two metal lines just below the heater core above the drivers fuel tank. Unfortunately you may need an extra couple of hose clamps as the two lines are different sizes. The hot side is 3/4", the cold return is 5/8".
No, truck had a valve on the supply side, then I just used vise grips to squeeze shut the hose on the return side.