How difficult is it to replace water pump on a 1997 dodge grand caravan 3.3L?

Very easy. You can do this. Just take off the serp belt by pulling down on the tensioner with a 15mm wrench. Then remove the three or four bolts for the water pump pulley. You will need to be under the vehicle for this. Then remove the five or six bolts for water pump. Pull the pump out and install new one in the reverse order. Just slip the belt off the water pump so you don't have to figure reroute the whole thing unless you are replacing it. Also clean the mating service for the pump before installing the new pump with the new gasket. Should take about an hour