I was actually pretty lucky with the bottom.
The refrigerator in my house, also a Frigidaire, has a big hump for the compressor
in the bottom rear. This one was basically flat. I measured the width of the bottom
and cut a piece of the deck board that size, then a piece the size of the depth.
It turned out that with the width board in the rear, the depth board sat fairly level.
Not exactly mind you, but close enough that I wasn't going to spend all afternoon with
a plane or running it through my tablesaw to peel the minute fraction of an inch of
thickness off the plank.
FWIW, that hole in the bottom is for a plastic mount the held the separater for the
pull-out trays. It really wanted to stay in there, and when finally finessed out
with a screwdriver it decided to take some porcelain with it.
The 12' deck plank had a little over a foot left of it by the time I had two width boards cut for the back, one width for the front, and four depth boards cut for the keg's base. Everything was fastened with deck screws.
Sittin' steady. I'm ready to head to EVLTWN’s the next day and meet Scott Mac. While I'm waiting, I guess I'll have a beer. Out of a can, since this has no plumbing hooked to it and the barrel's empty anyway.