You mean you invented a time machine, and that's all you brought back?? Sorry, just a comment about the immaculate condition. Amazing! Looks like it was stored in an air conditioned room from the day it was brought home from the store. Interesting seat post clamp arrangement. Stays above the seat post clamp is very unusual for a bike like that.

Keeping the rust away is easy. Don't leave it outside (or ride it) in the rain. A little wax once a year. If it has the original grease which I suspect it does, have it rebuilt with new grease. With 20-30 year old grease in the bearings it will last about two months to max of six months, before it needs new headset, BB, hubs, etc...,,,,BD