There are three ways to get to the Renaissance from the Baltimore-Washington International (BWI) airport:
Shuttle. Super Shuttle costs about $13 USD but may take a little longer as it may stop at several hotels en route. You can make reservations on their Web site at www.supershuttle.com. Reservations are not required.
Taxi. Taxis are available and will charge about $30 USD for one person.
Train. The MARC light rail system picks up at BWI. The cost is $1.60. Just get off at the Howard Street station and then walk 8 or 9 blocks to the hotel.
The trip from this airport to the hotel is around 8 miles.