Using CPAN.pm to install perl modules will require access to the internet from the machine you're running on.

IIRC this is not strictly true: one can have a local mirror of all the modules he needs, and then she can conveniently use CPAN.pm with file:// URLs. Then I believe (but I am not really sure because I've only given a peek into the module's docs) one could use CPAN::Mini::Inject on the machine with internet connection to resolve dependencies for given modules and mirror them locally.