Are the wheels metric 700c, or imperial 27". Older 27" tyres are still avaialable, but hard to find. 700c is standard for road bikes.

Are the teeth on the freewheel worn? You can still get freewheels (I use them) but you need the special tool to undo them.

It looks a fine utility bike, worth fixing up, but not lavishing lots of care on. The advantage of a rough looking util bike is that you dont fret when they inevitably get scratched or fall over.

Does the bike fit you? No point working on a too-small bike unless you want to give it to someone small.