Road 100%. Sidewalks are meant for pedestrians walking, not bikes. Is there a route that you can find that has a bike lane? Try your route on a Sunday afternoon where there might be less traffic, maybe around dinner time. Practice riding in the road/bike lane with cars. Don't give them too much room if you are in the lane as they will try to squeeze by you in the lane, forcing you curbside. You don't want to be there.