Sucess! The clutch disk appears to have been stuck against the pressure plate (likely due to being stored outside). A quick application of the starter with the clutch depressed and the tranny in 1st gear popped it free. Well, perhaps it wasn't all that quick. I spent the entire day battling the driveshaft/Ubolts/linkages etc, but by this evening the truck made it to the end of our driveway and back under its own power. My kid was thrilled! Thanks for the tips!
Stephan
