Well, I did the job in two parts without removing the vent duct (LHD). The first hour I took everything apart and worked out a way to get at the screw. Then I went inside to get over my anger with a glass of wine (well okay, 3). Had a nice diner made by my 13 year old daughter! YUMM! Back out the next morning with new positive attitude and it went very quick. Drained coolant, backed out screw, cleaned pipes, soaked new rings in coolant, put rings on hoses, tightened screw back down, checked pipes for play, filled with water and coolant / water came pouring out the passenger side door and drain!!! WHAT A MESS! Cleaned it up as best I could to protect computer as much as possible. Backed out screw again, checked rings, retightened the screw, added (less) water and no leak! Not sure what happened the first time so be very careful that the screw is threaded correctly and add water slowly with someone watching for first sign of a leak.
The best tip in the process is to use water for testing. I would have had a nightmare if I had put coolant back in to test.
Now any suggestions as to the best way to clean up coolant laced water soaked carpet?