If you want some of the simplicity of a single speed bike, want to climb hills and still get up some speed, I'd get be using a 3 speed Internal gear hub. Otherwise with 1 speed you might need a 40T chainring with an 18T sprocket or about 58 gear inches for your ride. A 16T sprocket, or about 65 gear inches is good for most rides, But you have special needs.
Last edited by xroadcharlie; 03-23-20 at 11:50 AM.