Agree that the HI on Cote de Liesse is miserable (but really cheap). Nevertheless, I also agree with ABG that the Marriott (directly connected to the terminal) + Sheraton & A-Loft (nearby) are very good choices, and are risk free for your morning flight.
The 747 express bus is a superb service; I'm just not sure about rush hours. Does it use a reserved lane?
Bon séjour à Montréal! ^
the 747 does not use a reserved lane (except maybe on Rene Levesque).