Best parts car for 1970 Duster project?

I was gifted a 1970 Duster.. that's missing most of the interior and rear axle and suspension... Primaily looking for Back seat .. rear axle rear Springs, spring hangersetc.. door panels and steering Column.. do the later 73-76 parts Bolt in? Do they use different rated rear springs ob V-8 cars? and what back seats will work? ie is a 4 door dart back seat a direct swap in a duster.. Thanks and sorry if this is posted in the wrong place.
Author: Frank1669