The zone list is in a configuration file saved in %APPDATA%\Paragon Chat\Config (enter that in a Windows Explorer window and it'll open the real location). By default, the zones in the file mirror those in the live servers, with the same numbers (there's internal reasons to retain the same number). You can add any maps that you want in there as long as there's no zone number conflict and you assign a chat room ID that is not used by another zone.
# Zone 1
# # Atlas Park
# Zone 3
# # Cimerora
# Zone 4
# # Midnighter Club
# Zone 5
# # Kings Row
# Zone 6
# # Steel Canyon
# Zone 7
# # Skyway City
# Zone 8
# # Talos Island
# Zone 9
# # Independence Port
# Zone 10
# # Founder's Falls
# Zone 11
# # Brickstown
# Zone 12
# # Perez Park
# Zone 13
# # Boomtown
# Zone 14
# # Echo: Dark Astoria
# Zone 15
# # Crey's Folly
# Zone 16
# # Ouroboros
# Zone 18
# # Abandoned Sewer Network
# Zone 19
# # Echo: Faultline
# Zone 20
# # Terra Volta
# Zone 21
# # Eden
# Zone 22
# # The Hive
# Zone 23
# # Sewer Network
# Zone 24
# # Outbreak
# Zone 29
# # Galaxy City
# Zone 36
# # Nova Praetoria
# Zone 37
# # Imperial City
# Zone 38
# # Neutropolis
# Zone 39
# # Underground Nova Praetoria
# Zone 40
# # Precinct Five
# Zone 41
# # Destroyed Galaxy City
# Zone 42
# # Underground Imperial
# Zone 43
# # Dark Astoria
# Zone 49
# # First Ward
# Zone 51
# # Underground Neutropolis
# Zone 52
# # Night Ward
# Zone 55
# # Fort Trident
# Zone 56
# # The Crucible
# Zone 60
# # Rikti Crash Site
# Zone 61
# # Peregrine Island
# Zone 62
# # The Hollows
# Zone 63
# # Tunnels of the Trolls
# Zone 64
# # Firebase Zulu
# Zone 65
# # Cascade Archipelago
# Zone 66
# # The Chantry
# Zone 67
# # The Storm Palace
# Zone 68
# # Paragon Dance Party
# Zone 69
# # Striga Isle
# Zone 70
# # Breakout
# Zone 71
# # Mercy Island
# Zone 72
# # Port Oakes
# Zone 73
# # Cap Au Diable
# Zone 74
# # Sharkhead Isle
# Zone 75
# # Nerva Archipelago
# Zone 76
# # St. Martial
# Zone 77
# # Grandville
# Zone 78
# # Bloody Bay
# Zone 79
# # Siren's Call
# Zone 80
# # Warburg
# Zone 81
# # Recluse's Victory
# Zone 82
# # Croatoa
# Zone 83
# # Pocket D
# Zone 84
# # Faultline
# Zone 85
# # Rikti War Zone
# Zone 86
# # The Abyss
# Zone 87
# # Monster Island
