There was a big story in Airliners magazine a year or two ago about one of the biggest airplane parking lots - Marana, AZ. Many of the planes there are in perfectly good shape and are put there if an airline needs:
-to rest them during slow economic times
-to put them on hold until a buyer/lessor takes them
-to leave them for scavenging
It was a great article, and was clear to point out that it is a private airfield and tours to the public are NOT given. Airlines pay a hefty fee to park their planes there and don't want people wandering around, guided or otherwise. The field is heavily guarded and patrolled.
I'm sure there are other genuine junk yards where there are nothing but fuselages and rudders laying around, but this one is among the biggest in the US desert.