1x10 works great and provides plenty of range.
I wouldn't do it on a 20+ year old bike that wasn't all that great to begin with. Clean the bike up and replace cables and housing. If you've already got the friction shifters, do that at the same time.
That's the best you can do on for it.
If you had a high end bare frame from the same era, 1x10 is often an economical way to get the bike rolling.