I've used XML::Simple for before and found it very, well, simple. Given the descriptions on cpan for twig (A perl module for processing huge XML documents in tree mode) and simple (Easy API to maintain XML (esp config files)), I'd say your description matches up with Simple very well.

If you do decide to go with simple, a word of advice: read the documentation. XML parsing is the type of process that you need to understand what the API is doing for you to prevent unpredictable results.