I wouldnt....i would prob have newborn in with me for as long as possible. I couldnt think of anything worse if baby woke at 5am for their morning feed, and i had a 4 yr old to settle back to sleep too. What would happen when baby has day sleeps ?Does your son play in his room during the day....coz him having the opportunity to do that would be very limited, esp in the first few months, when all they seem to do is sleep. I dunno, its a tricky one. I personally would keep newborn in my room.
GL .....