What I would do, indeed, is to install the module separately, into your own PERL5LIB directory using your own CPAN-settings. In other words, leave the distro writer's environment just as they expect it.

It has furthermore been my experience (I don't know about your distro...) that many distro vendors don't use CPAN. So, if you do, there could be conflicts.

When you're doing your stuff, put it in your directory of choice and make PERL5LIB (and CPAN's "PREFIX=") point to it. When doing their stuff, use their tools and make sure that PERL5LIB is defined to whatever they set it to; or completely undefined if they don't set it.