At the risk of sounding none too bright, I must admit I still have trouble "reading through" data structures, sometimes even "simple" ones. (Personally, I blame dyslexia...) When I am in doubt of what I have or how to process it, I usually turn to one of the techniques I outlined in Re: How can I visualize my complex data structure?.

I also like the "view" of a structure provided by atcroft's Re: I've got a hash of hashes how do i get my values out.

HTH,