
It's interesting that you couldn't get it in without removing the seat. I was easily (for pillarly definitions of easy) able to get mine out (but still kinda in place) and then back in (before I realized I'd be taking it out completely) and then back out (completely out of the Chinook) with the driver's seat in place. So you'd think it would also go back in.
One thing I noticed is that your Flexsteel driver's seat looks like it extends way back into the coach. I have Flexsteel seats too but a slightly different model. Maybe mine tuck up forward a bit more? Or maybe I could get my pillar out but not back in (although that seems to be against physics; but then having put new covering on the things I'd say they do defy physics in some ways

Rooney has had his out and in; I wonder if he removed the driver's seat?
I also have my passenger one out, but I kind of cheated on that one as I don't normally run with a passenger seat (have a custom tool box/map table there when I'm solo; seat when I have people along) so it was already out. Oh the glorious working space!
Which, there's no reason not to take out the driver's seat anyway because: Glorious working space! I haven't done my cab yet, but we did my buddy's same Ford cutaway -- removed the carpeting and put down real sound deadening material (two kinds) plus new vinyl (he didn't want carpet). We also put heat shield material inside the doghouse. I have GOT to do that to mine (which I call "the furnace").
Anyway, back to yours: Ah, looks so nice! And the flap is where it is meant to be, BEHIND the wall.