I survived the head replacement and trust me if this wagon hadn't been so hard to find in the first place I probably would have let it go, but I'm sure glad I didn't. My failure was certainly due to over heating. My viscous fan clutch was failing to engage and allowing the car to run warm. I never personally drove it in the red, but I'm sure the PO did.
Please vote in the survey I posted while I was in recovery over my head replacement:
603.96 Engine Head Crack Survey
I think the best advice is to try to avoid one that is already exhibiting the cracked head symptoms or negociate the head replacement cost into the deal and then take care of it like the guys on the form suggest and chances are good that you'll enjoy your car for a long time. As the survey points out with 24 respondants so far. A cracked head is far from a sure thing.
Good luck,