Welp. Had a morning free of meetings, so spent it in the garage. Everything bolted back together, set the valves, turned the key and it immediately fired up and idled perfectly. Drove it around with no deck to confirm it was operating fine.
Purchase price: $250
Plugs, gaskets, misc hardware, rust inhibitor, JD paint, couple new idler pulley's, led headlights: $135
Cleaned all surface rust, used rust inhibitor, painted over all areas (tractor and deck), pimped out the headlight buckets and put LEDs in, seems to be a pretty dang good value.
Here's a few pics from the process. Thanks again for cluing me in on the Woodruff Key.