Are you to code for internal use, for a variety of customers, or for wide distribution? The answer should determine how many versions of perl you'll want to have around. They can be installed with a version prefix allowing the binaries to mix in the same directory.

Work to forestall institutional resistance to installing additional modules. Plenty of arguments for that can be found here at perlmonks. You can't easily prevent people from installing modules in their home tree, and it would be useful to help them do that. It's not hard to write a perl program to create a ~user/.cpan/MyConfig.pm file set up for ~user/lib/perl5 and to provide $PERL5LIB to the login shell environment.

The advice about cvs is crucial. Make sure it is a somewhat dedicated development machine and have your many perl versions on it. You don't want production concerns and development needs to interfere with each other.