Before you dive too deep into what could be a bottomless pit, you need to do a little testing.
Plastic or rubber mallet, tap around the transom and under the hull. You must hear a nice solid tap sound, if you hear a thud, that is a waterlogged (rotted) place. Same thing on the decks and floors, any boat of that vintage will have wood decks and floors, and depending on where it lived will have a fairly high chance of needing replacement.
Ebay is gold for finding used parts.
Steering is generic, throttle/shift cables must have the chrysler connections to work.
Any generic key switch can work.
Fuel lines are a given, they'll be junk.
Fuel tank? Put a rag on a stick and wipe around, if you come back with a stick full of goo, you have problems.
Good luck with it, not sure what you've got to spend but free boats are usually very expensive.
Marble Falls/Seadrift TX