If it worked when you bought it and it has less than 2,000 miles on it, why does it need a complete rebuild and upgrade to be "useable"? I've owned several bikes that were a lot older than yours that I rode stone stock after basic maintenance and taking care of minor issues like cables, brake pads and tires. I had a 1995 Trek 1500 that I rode up until two years ago. The only change/upgrade it ever got outside of the usual consumables was a more modern set of rims. My wife rides a 1993 Trek 820 that is stock except for some comfort items like a different saddle and handlebars. I cleaned up a 1980s Schwinn Traveler for my stepson to use when riding with the grandkids. It too is completely stock except for consumables and comfort items.

Your bike should still be in pretty good shape with less than 2,000 miles on it, so outside of some of the normal consumables (all of which are still available) there is no "need" to throw big money at a complete rebuild and upgrade if all you want is a "usable" bike.