Here is the site for BWI Airport:
http://www.bwiairport.com/

I called the hotel today and verified the shuttle rates and times. If you are interested in this option the rate is $11 one way, $18 round trip. Leaves airport from baggage area 6 & 7 every 1/2 hour. Our hotel is the first stop. Also leaves hotel every 1/2 hour so would probably be the last stop returning to the airport.

Also for what it's worth I spoke with a reservation clerk today and requested a room on a lower floor. Seems this hotel is the tallest structure around at 32 floors. She told me our rooms are not all on specific floors but scattered throughout the hotel.
You will also have to provide a credit card upon check-in.