I don't know about the 94 models but later years have a water heater bypass system that allows you to drain the water heater and fresh water tank and only pump antifreeze through the plumbing.
Most of these have a suction tube that the pump uses to draw antifreeze from the jug and pump it through the system. If you don't have such a system they are available in many/most RV stores.
Clay WA5NMR - Ex Snowbird - 1 year, Ex Full timer for 11 years - 2004 Winnebago Sightseer 35N Workhorse chassis. Honda Accord toad.