I've thought about this many times. We have two windows in the bedroom and two in the living room that can open as emergency windows. Half of the window in the bedroom on the driver's side is covered by the headboard but unlatches easily with a small tug.
There are three steps to open the window which seem easy. One of the steps is removing the screen so really only two crucial steps. Our windows are electric, the windows swing open from the bottom and there is plenty of room to fit through as they are at about 4 feet wide and about 18 inches tall (that open). It is a long way down but there is really no alternative unless we have a chance to exit the entry/exit door.
Safe travels,
MM.