Sounds like you don't need to bother with CPAN module at all

cpanm

Re: Perl + CPAN torrent or ISO: CPAN::Mini, Portable,

cpaninject, minicpan / CPAN::Mini / CPAN::Mini::Inject - Inject modules into a CPAN::Mini mirror.

dpan - create a DarkPAN from directories

How to install a DarkPAN module?, RFC: Private CPAN In A Box