Naturally I didn't get as much done as I wanted. It's hard to make progress when you only have ~1 hour to work and you get stuck on something. The 4X mm nut that goes behind the hub gave me issues. The FSM says to shift the assembly int 1st and reverse simultaneously to keep the mainshaft from rotating but because the reverse pinion on the countershaft is helical and unsecured it pops out of position allowing the mainshaft to spin. Eventually my wife came up with a solution to use a small wormgear hose clamp to hold the reverse pinion in place. Torqued to ~140 ft-lb (FSM calls for 94-174 ft-lb) and staked in place:
With the delays due to the mainshaft nut I was only able to install 5th gear and the thrust washer behind it:
All that's left on the mainshaft are a couple of c-washers and their retainer, the rear bearing, another set of c-washers and their retainer, and finally a c-clip. After that a spacer, the 5th gear pinion, rear bearing, and nut are installed on the countershaft and this part of the assembly is complete.