I live in hilly Cornwall, and I went singlespeed last month on my road commuter. It’s a 42-16. I love the quietness and simplicity.
I find most hills are surprisingly managable, I get some momentum going on the approach and just charge up them. I spin out quickly on long steady descents and now get overtaken by other cyclists on the flats, but I have yet to be beaten by a hill – although I’m building some significant leg and arm muscles from heaving on the bars!
Gritting your teeth on the steep bits and charging up is compulsory. If I’m weakening I tend to remember that the Tour de France was ridden singlespeed until 1937 – imagine racing up the Alps with no gears!
Remember there are actually three gears – pedalling sitting down, pedalling standing up, and getting off and walking…