So what I thought was a bit true. The liner is sort of trapped under the edge of the body and the lower side molding. The side molding is flexible at the edge, but not at the body seam, obviously I don't want to break it! So I can almost get to the tank. When I pulled the liner to the position in the picture, I heard a clank, and noticed that there was no screw in the tank mounting hole. I managed to recover the screw, and I was able to rethread it, but as you can see in the picture, it's a bit rusty. Perhaps, after coming loose, it had allowed the tank to rattle around. I filled the tank up past the first lower grommet, and haven't noted any leaks. The hoses and their clams look solid. (I'm hoping that the rattling around hasn't worn a hole in the plastic!)
If I could get the liner the rest of the way out it would be a lot easier to look at the tank. I'll try to get the tank unhooked enough where I can look at it . . .
VVV NEW VVV
Finally, some success! You really have to twist the liner clockwise (when looking down) about the front corner of the lower molding while pushing it inwards. It is still a wrestling match! But I'm still fighting things that are too tight to work with. There seems to be enough play in the lines to pull the tank out, but not enough slack in the fill hose. And I can't seem to get the fill hose disconnected from the fill nozzle. I can move one relative to the other, but I can't get seem to get them to move far enough to disengage.
If there were seals between one to the next, I've probably messed those up.
Right now it doesn't appear that I have a leak. I have the tank half full and nothing seems to be coming out. Previously I had filled the tank and two days later I was getting a low level light. When I tried to refill it, then it looked like there was fluid draining from that portion of the car. As you can see from my pictures (prior to refilling) I was down to the lowest level of the tank with only a half dozen uses.