There's a lot of stuff in CPAN. Focusing on the "majority" of modules is misleading. Focus instead on the modules that are of interest to you. Find them in CPAN, download them, and look. If the .tar.gz containing the module contains only .pl and .pm pieces (in addition to README, Manifest, and .t files), then you can install it in your own directory. The ones to watch out for contain .xs or .c files. Those require that you compile parts and put them in places that require administrative access to get to.