Seattle is a weird hybrid that probably could be a model for what is realistic in the US. There a tons of walkable neighborhoods all over the city to provide daily necessities but you really do need a car to make that trip across town or even from one neighborhood to the next in some cases.
Yea, the hills and water really mess up public transit routes in Seattle, making it a lot harder to get around by bus in any sort of efficient timeline, especially around the Queen Anne and Beacon Hill areas.