Actually, those are reserved for hams with a MAILING address in Alaska. The station doesn't actually have to be in Alaska (HINT HINT).
You could get a PO Box & remailing service out of Alaska but that would enable other stations to get credit for Alaska in DXCC & WAS, as there would be no way to show that the original poster's station was actually in NJ instead of where the license says he should be.
FCC simply requires a mailing address. Where the station is actually located depends on the licensee, and can be anywhere in US territory.
DXCC and WAS do not go by FCC license info. They go by either paper QSL or LOTW.
With a paper QSL, you have to indicate the station location
for it to count for the award.
With LOTW, you have to create a location file that identifies where the station actually is. LOTW allows multiple location files, for the ham who has multiple station locations. For example, if I had a place at the NJ beach, and operated from there, I'd create another LOTW location file for those contacts.
In the case of remotely-controlled stations, Echolink, etc., what matters is where the radio stuff
is, not where the control operator
All that said, the idea of using an Alaskan PO box to get a call that one otherwise can't get is against the spirit of the rules, IMHO.
73 de Jim, N2EY