Alaska meshes

[brundlefly]

i found these alaska mesh files on flightsim.com (4 files):
alaska_1.zip
alaska_2.zip
alaska_3.zip
alaska_4.zip

anyways ,these are all EXTREMELY large downloads (one of them  is 394 MB!) and i was wondering if anyone has used them because i'm not sure if all of these files are separate parts that have to be individually downloaded,or if they are just different versions.