Fortunately, I found a place near my office that accepts used coolant and doesn't even charge a fee for it. I stopped there on the way to work, and they pointed me at a 50-gallon drum into which I poured the green goop.
Meanwhile, I heard this morning from my father-in-law, who said that Lisa had made it to Crescent City (near the Oregon-California border) and was doing okay. They continue to stay in contact on the 40 m radio band.
This evening I need to remove the radio console from between the front seats of my minivan to give access to the "doghouse" so that my mechanic can get at it when he starts a full tune-up on the vehicle tomorrow. Unlike the emergency repairs on Lisa's van, this is scheduled maintenance, being performed by the mechanic who installed the engine in my vehicle.