Okay, I was able to spend a couple of hours today, with my welder and the beast, I was able to weld, in both sides of the car under the 1/4 window, at the floor level behind the interior panel. I did weld under the car for the most part, I was able to tack weld, then stitch weld the panel from the inside, not an easy trick with the bottom frame part obstructed my hands and welder gun.
But it is now done, even removed the screws and welded the holes shut. The next step is to slap on some seam sealer, from both inside and underneath the car floor. I was thinking of drilling 3-3/8 drain holes, so no water will stay trapped in this cavitie, thi will be followed by trusty Tremclad red oxide primer and topcoated with Sure seal rubberized undercoating. That should take care of this matter.
The welding in this area was tough, the old sheet metal was corroded enough to make the welding a bit more of a challenge, only burnt through on a few spots. Welding inverted is not too bad once you get comfortable and get some practice, by no means am I a real welder, but can get by with what I have.
Here's one for just4don, gonna have my 15 year old step-son and his buddy get under the car, with my supervision to wire wheel and clean up the floor and frame, so I can paint under there, no this is what step-sons are for, mind you I am going to pay them $50.00 for doing it, which is a real deal IMHO................LOL Fred