For anyone having texture problems:

Go to gmod in your library, right click & browse local files.
Click garrysmod folder.
Click cfg folder.
Click mount, and edit the text, this can be done with notepad.

Paste this, and remember to delete the // before cstrike.

C:\Program Files (x86)\Steam\steamapps\common\Half-Life 2\ep2

Save it, and you are done! Ask questions as needed.