And a variation on kyle's suggestion is that from within Perl you could execute a trivial tcsh script that loads up the tcsh configuration and then prints out the environment. Parse that output from within Perl then load up a Perl configuration.

RE (tilly) 3: Get default login environment demonstrates the basic technique. (That was for picking up a login environment.)

This is convenient if your configuration has complex conditionals that you don't want to parse directly in Perl.