Suggestions/input wanted....(kinda long)

I'd do like suggested and do the frame, and roll bar. Keep some skinnies on it to roll it around.

What about the suspension - is that done ? if not - then do that.

After that I would get the trans and motor fitted, doesnt need to be the 408, just a plain empty block (could be a 273). This will allow you to get the clutch linkage, shifter position sorted out - not sure whats needed with the 5 spd change.

Next the interior, the brakes, and you area about done, at least with the mechanical stuff.