HEEERE GOES! 
For the north boundary, the screen size is 1200. There are 10 JLabels on the top row. The size is 114 by 80. But I think I'm going to add about 5 pixels of extra room just in case because there is quite a bit of white space. 
Therefore, for the north boundary, the x-value would start at (40) and would start at y-value (30) <-- give or take a few. 
Start Adventure --> (30, 40) 
Borgin and Burkes --> (149, 40) 
Room of Requirement --> (263, 40) 
Roland Kerr College --> (378, 40) 
Camelot's Annual Tax --> (491, 40)
Tardis --> (605, 40) 
Redhaven --> (719, 40) 
Room of Requirement --> (833, 40) 
Piccadilly Circus --> (947, 40) 
St. Mungos' Hospital --> (1061, 40) 
For the east boundary, the length of the screen size is 1200 but there is a lot less room. 
Platform 9 and 3/4: (30, 20) 
Speedy's Cafe: (30, 100)
Avalon: (30, 180) 
Isengard: (30, 260) 
Taxi: (30, 340) 
Grimmauld Place: (30, 420) 
Room of Requirement: (30, 500) 
Quidditch Pitch: (30, 580)