To bypass the heater core (a situation I've been living with since I did it as a trail fix about a year ago) you just need to disconnect it, and then use one hose to make a loop from the connection that sends water to the heater core to the one that returns it to the engine.

So there are 2 hoses running to the heater core. One delivers hot water to it, one returns the hot water to the engine. Both go into the cab on the passenger side of the vehicle at the back of the engine bay; they clamp on to pieces of fragile plastic pipe sticking out.

By looping one hose around and taking the heater core completely out of the loop you stop any leaks in the passenger compartment, but also make it impossible to have heat or a front window defroster; 2 things necessary on a vehicle in Colorado almost year round.

It's easy to do; just takes a couple of minutes. The hardest part is getting off the old hoses.