I need help with a fixed gear I'm planning for a gift. I’m currently cleaning up my fixed gear to give to my step son for a college commuter and would like some advice. Here is what I have:

Schwinn world sport frame conversion with Surly flip-flop rear hub re-spaced to fit the 126mm rear drop outs with a 20t Surly cog and lock ring. The crank is an old Shimano bio-space with a 39t single speed ring. My current setup has a straight chain line.

Here are the questions:

Should I change the gearing? He lives in a less hilly town and is in better shape.
Should I add a freewheel on the other side of the flip-flop hub? I have read that they are not very useful and can be hard to get a good chain line on a flip-flop…

Let me know what you thinks

Thanks
Kevin