What a beauty. If this bike were mine I'd aim to do as little as possible, any bright ideas you get are just going to spoil it (I speak from a lot of experience in this department). You are crazy to want to change the crankset OR the drillium rings. I would say clean and polish, re-grease all moving parts, spring for some new hoods and saddle as well as disposables like cables, tires and chain and you should be good to go. Take your time and whatever you do don't mess this one up! I would almost suggest picking up a low end ten speed to work on and practice your bike maintenance skills before even touching this one, but that's just me. Congrats on a great find.