If you do decide to pursue some of the upgrades suggested here, look to see if there is a bike co-op near where you are. That might be a source for inexpensive period parts (such as a matching RD). Alternatively you can post a WTB ad on the for sale forum forr hard to find components. Prices here can be quite reasonable.

​​​​​Throw a small toolset in your vehicle. If you see a trashed bike either grab it and take home or take off what you need. I recently stripped off a set of fenders rushing desperately as a garbage truck advanced down the street.