This is kinda what PERL5LIB is for. Kinda. But it is useful for this - I do something very similar in automatically installing a bunch of modules during a build process - but they get installed into the build tree. So my script just sets PERL5LIB to include the lib directory I'm installing to, and then sets PREFIX and LIB, or --install_base, depending on whether it's a Makefile.PL or Build.PL-based distribution, and then prereqs are found.

In your case, you may want to just set PERL5LIB=C:\lib in your system environment, start a new shell, and then work from there. (Maybe - I can't completely tell why you're using a local install path, there are so many reasons why you might be doing this.)

Good luck.