TH350 in my Project Truck Fubar (see pics)?

[badpeanut]

I recently bought a 1972 Chevy 1/2-ton 4x4 with a TH350. The previous owner stopped driving it in 2002 because "it wouldn't move anymore". Even though the column shifter and linkage was hooked up and looked okay, I couldn't feel any of the detents in the transmission. I dropped the pan tonight, and found the S-hook hanging in the pictures loose in the pan. Also the detent roller/lever does not contact the cogs because the piece with the cogs is flopped out of place (pardon my highly technical terms). What all is wrong here?

I also included a picture of the truck the day I brought it home (rough body but fairly unmolested overall).