Is this the right way to do it? Is something like that (or a better solution) available from CPAN?

Someone once asked me to help them learn the right way to fish. My answer to that person was you learn the way to fish that is right for you and the kind of fish you want to catch.

Same is very true in my humble opinion about your question. There are many right ways to do it.

First off I'm a big fan of using XML::Simple to parse in an XML file that I have stored on the system that the script is going to run on someplace predictable. Just so happens that with XML::Simple this can be a no brainer because the default behavior for the method XMLin, one of the methods the module defines, is to look for a file with the same base name as the script you are running, in the directory the script is running from with the extension ".xml". The module also provides for pathing behavior as well.

The module you show in your example is a good start. One trick I've used is to use $0, strip off any extensions to it and use that as a key into my XML file for where the application data lives.