The Westin Atlanta Perimeter North Hotel is about a 10 minute walk from the Medical Center Station on the red rail line.  The hotel also provides a free pick up service at the Medical Center and Dunwoody Stations if you call ahead to make arrangements.

To get to the station you must be on a red line train.  If coming from the airport before 7pm, board a train labeled “North Springs”.  After 7pm take the first train that arrives to the Lindbergh Center Station, exit the train and wait for the North Springs train there.

If you plan to walk, once at the station, exit on to Peachtree Dunwoody Road and be sure to cross over the street before turning right.  Walk about 10 minutes, going under the interstate, then turn left on Concourse Parkway (see walking map).

For more information, see:
Tips for Riding MARTA to/from the Airport
Top 5 Hotels Closest to MARTA
Using Google Maps for MARTA Directions
10 Easiest Destinations to Get to on MARTA