Practically you are not allowed to bring onboard and object that is too large to fit between passenger seats and this include luggages. However you can get away with bringing luggage onboard if the bus is not crowded. The only problem with that is that the Deuce is always crowded.http://www.lasvegas-how-to.com/cat.php
You can do it if the luggage is not too large. Would be best if using it very early in the morning when not so crowded.