Lots of old bikes can be easily improved. Older road bikes are often best suited to casual riding around town, rather then the fast riding suggested by drop bars. WIth bigger tires and wide-range gearing, older mountain bikes make even better town bikes and touring bikes, but narrow straight bars aren’t the most comfortable way to see the city. In either case, an upright bar with some rise and sweep can help.
For bikes like this Bridgestone MB-5, the VO Tourist handlebar helps. Many similar bars are available these days. Comfort is close at hand.
The Tourist is 57cm wide, with 75mm of rise and a 60° sweep.
This classy grey bike on the VO blog depicting a Tourist handlebar is mounted to a 1984 Univega Alpina, purchased off Craigslist for about $100. I built this bike for Katie, a friend and co-worker.