You can indeed change the path and the environment before invoking Perl. For example, I use a batch file like this to set up the environment for every version of Perl I use:

@echo off
set base=%~dp0
path %BASE%perl\bin;%BASE%c\bin;%BASE%perl\site\bin;%PATH%
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This file lives in the base directory of every Perl installation I have, like C:\strawberry-5.10 and C:\strawberry (which is currently 5.12). If I want to switch to a particular Perl, I invoke the batch file in the appropriate directory and thus switch the Perl for that shell window.