Welcome to the Team Tom!
In 1969 they still had coil rear springs as they eventually went to a leaf sprung rear in the 1977 and newer wagons. That said, I don't think any thing but your power train will transfer directly to the Kingswood without modifying either the part or the wagon.
As a for instance; I cut out the bottom front of my Impala core support to use a pick-up truck sized radiator in my car for the added cooling surface area. If you don't mind modifying your wagon many parts will fit. You could probably section and channel the pick-up truck frame to fit under the wagon to reuse pick-up suspension parts, but that is looking for work in my opinion.