I tried YAML just now and I was very disappointed by it. Not only did it take 14 seconds to load what Data::Dumper can do in .3 seconds, but it is buggy as well. It died on the hash key below until I supplied by own quotation marks around it!

  Trade Route (Eastern Range, Yellow):
[download]

Update: Storable beats everything else so far, among methods that pull the whole data structure into memory:

Storable: .17 secs
Data::Dumper, byte encoded: .31 secs
Data::Dumper: .32 secs
YAML: 14.2 secs