Its not well signposted and i got lost a couple of times in my visits over xmas etc but you can enter the main entrance - with the cafe, M&S etc - via the bus stop and then get into the back lift to the A&E floor (which i think is floor 6) and walk over to avoid the walk up the hill.
I visited RSCH nearly every other day for a couple of months in Nov/Dec looking after my Dad. A&E services and experience, as Piers Morgan and many others have shared , were pretty difficult. My Dad was on a trolley for 27 hours before being transferred to a ward and its undignified, a bit...