I've a duck sitting on a nest just under a small evergreen outside my front door and near our garage. I realize it can take up to 28 days to hatch. But, we are pretty far from a lake. Anything I should do? My husband drives his car 4 feet from the nest every day. Should we stop using the garage? I'm not sure how many eggs there are and am not sure how many days she's been sitting on them. (We were out of town for a bit)

No, you don't need to do anything. My guess is that it is a mallard duck. Ones that nest in towns or near people are typically fairly tolerant of disturbance such as foot and vehicular traffic. The ducklings will walk to the nearest water source once they hatch. It might take them a little while, but unless it is miles to the nearest body of water they should do just fine.