I think I might have my trailer side bottom gap filler solution!
I have one piece of FRP left over from my FRP side skirt experiment and it seems to be the perfect depth to attach to the bottom front of the trailer. It will be reinforced with a 1"x2" frame and will be mounted with two hinges to the bottom edge of the trailer. It will swing up into the horizontal position and git locked into place with some support bars similar to my access doors. The front edge of the gap filler will be about 2" in front of the pivot points of the hitch. I might be able to attach an extra 6-10" piece to the truck's extended diffuser to take care of the remaining gap. The front stabilizer wheels will just clear the top of the cover when the wheels are stored.
Fer storage of the bottom gap cover, it should be able to clear the ground if I let it just dangle in the vertical position. If that doesn't work, I'll probably try either a magnetic attachment or just a clevis pin on one side.
