This is what I do:
Extract the mod somewhere. I have a mods folder specifically for unpacking stuff that is no where near my Morrowind folder.
If there are textures:
- drop the meshes into the textures folder.
- open mesh in Nifskope.
- go to texture property and look at texture
-- remove all folder trees so that there is only the texture name and extension (.bmp, .dds, .tga)
--- example: blah\poo\ni\derp\waterloo.tga TURNS INTO waterloo.tga
if there are no textures:
- open mesh in Nifskope
- look at texture name - is it vanilla texture?
- open Irfan View Thumbnails (download Irfan view if you don't have it)
- browse to TESIII CS disc Texture folder
- wait for 3000+ textures to load
- extract the necessary textures to a junk folder (right click, browse to output folder, click)
- put meshes into the junk folder
- re-open mesh in nifskope
When done, you can clean up (remove files you added/moved) or delete the extracted mod and then re-extract it.