The maps for these zones are definitely there in the VPK files. They actually are in the NrVObm.vpk file, and have the following names:
nrvobm_antonica_east.dds
nrvobm_antonica_west.dds
nrvobm_commonlands_east.dds
nrvobm_commonlands_west.dds
nrvobm_enchanted_lands_east.dds
nrvobm_enchanted_lands_west.dds
nrvobm_everfrost.dds
nrvobm_feerrott_east.dds
nrvobm_feerrott_west.dds
nrvobm_nektulos_forest.dds
nrvobm_orcish_wastes.dds
nrvobm_thundering_stepps.dds
map_lavastorm.dds
nrvobm_tiles.dds
As for their being encrypted, it is probably true, as they certainly aren't regular DDS files.
Regarding what Vikan Karo mentions, it is not true that VPK files contain mainly ambient and combat sounds in VOC format. First of all, the 418 VPK files contain a total of around 190,000 files of all kinds; basically the whole set of assets EQ2 uses. They are in a variety of formats, but sounds in particular are in WAV format, while the voiceover files come in MP3 format.
VOC files, of which there are around 20,000, are actually data which describe a composition of simpler assets that together form a complex entity. The definition is quite vague, but that's because they're used for pretty much everything: zone rooms, game objects, characters, monsters, character accessories, etc. EQ2 uses a very interesting file format, which I want to start documenting as soon as possible. I'll start with the VPL/VPK file format, which is quite simple. In the meantime, if you're curious and want to see the whole list of assets,
grab it here.