in reply to Installing CPAN modules without using 'ppm'
You might consider using Mini::CPAN and its minicpan utility on a computer with internet access to create a small mirror of the latest files on CPAN. Burn that to a CD or two and bring it to the machine with the air gap.
You can set your CPAN repository url to file://path/to/mini/cpan file://localhost/path/to/mini/cpan in the CPAN config file and it will use your CPAN mirror as if you were connected to the internet.
Update:
In response to a chatterbox comment about the URL format, here's what I use in my CPAN Config.pm (with the mini-cpan repository in C:\cpan):
'urllist' => [ q[file:///C:/cpan] ],
It's equivalent to:
'urllist' => [ q[file://localhost/C:/cpan] ],
-xdg
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