Motel-style dormitory with smoking rooms

Kimberly, it seems like weatherstripping the exterior doors would be an easy choice for energy reasons. Exterior doors are usually weatherstripped, anyway. Whether or not you HAVE to do it? The letter of LEED would require it, and probably for good reason—the ETS could leak through the exterior doors and into other living spaces. Penetrations are typically things like ducts, wiring runs, piping, etc. Anything that interrupts the air barrier between units. (For more on this topic, check out LEEDuser's strategy page on dealing with penetrations for IEQp2.) Prefab units may help, but I wouldn't take it for granted. Carefully review the credit requirements to make sure that the units will be air-sealed to the extent required, and perform blower-door testing.