Replace water pump

2001 Isuzu Trooper V6 3.5 4wd, 126k miles

mechanic showed dried coolant spray on engine just above water pump, diagnosed as leak either from water pump or failing gasket. Amount of leakage not enough to drop reservoir level a few ounces below max level. Recommends replacing pump, could just be gasket but no way to verify. Also recommended replacing timing belt (which was just replaced @ 90k miles). Engine runs fine, no overheating problems, my wife maintains this car meticulously. She is now concerned about a failing water pump on an upcoming 500 mile trip, does anybody have any suggestions on how to proceed?