I don't know how hilly SF is, but the Netherlands does have some areas that are somewhat hilly. With a bike with gears it's not much of an issue. You go slower

I don't know how hilly SF is, but the Netherlands does have some areas that are somewhat hilly. With a bike with gears it's not much of an issue. You go slower yes, but it still works great. In fact I prefer to bike in the hillier areas because they tend to be less windy than the flat land near the seaside. From age 12 to 18 I biked 12.5km to high school each day (and 12.5 back home), so even moderate distances are certainly doable. It's fun to think that in total I biked around 40,000km to school, approximately the circumference of Earth. It really helps to say in shape; I know people who bought a car and in a few years they were obese.