Hey Rick, I think the 72 had the Frigidaire compressor which is a gem of a compressor in my opinion. The clutch replacement is no big deal as the part was called a "field replacement part" and requires no special tools or knowledege to replace whereas the replacement of any other component of the system will require reclaiming of the freon and flushing of the system at a minimum.
I would opt to keep that compressor and replace just the clutch and let a cerified A/C tech add the proper amount of freon. At that point you will know what if anything else you will need.
As to the second part of your question you will need to make sure the bowden cables are free and moving the proper components of the duct work and heater valve and as was mentioned be sure the heater hoses are connected for correct water flow.
Good luck!!!!!!! Hobert
