Well, I owe you all a report. I took it to a shop with a Jim Carter repair kit for the U-joint (Made in Argentina). But the U-joint seems fine, good and tight. It centers up when in gear on the lift.
You are right, Stuart. One mount looked okay but the other one was broken in two. After I found the U-joint was okay I had to order new mounts, again from Jim Carter, and we got those installed. So now it is perhaps a little better, but not a whole lot. The mechanic is stymied and so am I.
My plan now is to drive it close to home and wait for it to get worse unless any of you have a better idea for me.