for make a zone you need :
a) a 3d modeler
(freeware :gmax ; blender)
b) a picture editor
(freeware :gimp)
c) a picture explorer : (if you have 10000 texture file
(irfanview )
d) a good library directory
e) a "fast load zone viewver" :
eqzoneviewer but the devlopper stop the dev not easy to find
i will be put it somewhere soon.
f)dongeon builder
g) S3DSpy
h) openzone