Well, that was all very interesting. Thanks for the first clue as to how to go about it. For others like me who haven't wrestled with Ford headliner retainers, etc here is how it went. The retainer pins are one way devices with barbs like on a bee's stinger: they go in, but won't come out without damaging the barbs. They can be re-used but it might be worth ordering a few ($8 for a pack of 4). Trying to pry them out with a couple of screw drivers won't work because you have to get right into the centre shaft or you weaken the plastic and the top tears off. I went out and bought a trim remover. It looks like a thin, baby crowbar and let's you pry right at the centre of the pin where the plastic is strongest. Even so, you have to watch what you are prying against, or you will damage the headliner. I only took off the pins along the back (4) . It seemed to be asking for trouble to take the whole thing down. The two nuts are hard to get at and require a 10mm deep socket with a 1/4 inch drive. The nut and washer are fastened together which helps installation. Pretty fussy job, but it came out OK. I will have to get one new pin to replace the one I broke.
Meanwhile, I am designing and buiding a system that allows me to use the TC as either a mini repair shop (attachments for a vice, bench motor, work bench, tool caddy etc) or re-configure it into a camper. Both set ups allow the back seat to stay on place for travel and then fold up for work or camping. We take the inaugural run next week. I will try to post some pictures when it is presentable. Lots of fun with the welder. Thanks again for the help.