In the hopes of making this process simpler, we're making use of perlbrew. It feels quite promising so far. Our previous module setup was complex and has gotten messy since the person who maintained it left.
To install modules into my test environment, I've been using cpanm to install from public CPAN, but am using the older cpan shell in cases where I have to apply patches using distroprefs (which I just learned how to do).
We have a couple of environments that require a very limited set of modules, and we're looking at using Pinto for those.
Our transition is far from complete: one of the things we're trying to determine is the best place to put our in-house modules. My first impulse was just to hand-create a subdirectory under site-perl and simply plunk the modules there, but I'm now thinking I should query wiser, more experienced heads before doing so.