Got a questions for those familiar with the BWI area.

Some friends are having a big convention over Memorial Day weekend but, due to a certain hotel backing out on a signed contract (they're working on that aspect, too), they have to rebook the whole thing. Not good, given the holiday weekend and large number of rooms (30 or so, some of them doubles) they need.

Most of the people are coming into BWI airport, on very tight budgets (think 'poor starving college students'), and without cars. The original hotel had an airport shuttle. They're busily calling other hotels with shuttles as well.

What I was wondering was, are there any hotels that are close to the airport without shuttles, but reachable via public transportation? Is there even public transportation that goes to the airport? I guess there's the train there. They don't want to have people riding around on a bus for hours, obviously, but is there something maybe on a bus route nearby? Or other creative options that wouldn't show up on a casual search of the BWI immediate area?