Take the Uptown A-C-E* (the blue line) or the Uptown 1-2-3 (the red line), one stop, from 34th Street-Penn Station to 42nd Street-Times Square.
Transfer at Times Square to the S shuttle train, east across 42nd Street, from Times Square (West 42nd) to Grand Central Station (East 42nd).
Transfer at Grand Central to the Uptown 6 train (of the 4-5-6, the dark green line). Take the Uptown 6 trainone stop to 51st Street.
You will exit the subway at 51st Street and Lexington Avenue. From there, it's just one block north, and three avenue blocks east to 52nd and 1st Avenue: Lexington Avenue ---> 3rd Avenue ---> 2nd Avenue ---> 1st Avenue.
You will be able to tell which way is north/south/east/west because you will exit the subway on the east side of Lexington Avenue. The west side of the street is the Downtown side, and the east side of the street is the Uptown side.
You don't have to take the subway; it's 2 blocks. Penn Station is at 34th Street between 8th and 7th Avenues, and 520 8th Avenue is between 36th and 37th Streets.
Take the Uptown E train (of the A-C-E, the blue line) from 34th Street-Penn Station to 53rd Street-5th Avenue. Fifth Avenue is one block west of Madison Avenue.
The closest subway station is the 42nd Street-Port Authority Bus Terminal station (at 8th Avenue) on the A-C-E (the blue line).The next closest station is the 42nd Street-Times Square station (at 7th Avenue) on the N-R-Q (the yellow line), 1-2-3(the red line), 7 train (the purple line), and the Sshuttle train (color grey) to/from 42nd Street-Grand Central Station.
Take the Uptown 6 train from 33rd Street (at Park Avenue South, 1 block east of Madison) to 51st Street.The 51st Street station on the 6 train is connected to the Lexington Avenue-53rd Street station on the E and M trains, so you can transfer without exiting the subway system.Transfer to the 53rd-Lexington station, and take the Downtown E train 2 stops to 7th Avenue (at 53rd Street) or to the next stop, 50th Street (at 8th Avenue). The walk is about equidistant from each station: 3 street blocks or 1 avenue block.
Take the Downtown 1 train (of the 1-2-3, the red line), 1 stop, from 34th Street-Penn Station to 28th Street (at 7th Avenue).
Buchanan Street subway station was created in 1896.
Merkland Street subway station was created in 1896.
Merkland Street subway station ended in 1977.
West Street subway station was created in 1896.
Bridge Street subway station was created in 1896.
Walk west to Lexington Avenue and north to 53rd Street, and take the Downtown E train (of the A-C-E, the blue line) from Lexington Avenue-53rd Street to 34th Street-Penn Station.
The American Girl store is at the corner of 5th Avenue and 49th Street. Take the Uptown E train (of the A-C-E, the blue line) from 34th Street-Penn Station to 5th Avenue-53rd Street. Then walk 4 blocks down 5th Avenue to 49th Street.