https://thepiratebay.org/torrent/3593146/Alien_vs_Predator_2___Primal_Hunt
http://files.tbbcbase.net/AvP2MasterServerPatch_Latest.exe
https://umpparty.stargatebase.net/downloads.php
http://tbbcbase.net/serverlist
Download the torrent then download the tbbc master server patch and run it to play the game (uhh put the server patch in the same folder as AVP2)
The umpparty contains over 625 custom maps with their own textures, sounds. It will take 5GB.
In the options menu (of the game launcher, not in-game) type in -rez ump2 (to load the entire folder of maps)
for specific maps type -rez map.rez (example: -rez suk-stronghold_2.rez
Most of the singleplayer custom mod maps should appear in the custom skirmish maps next to the singleplayer marine, predator, alien campaigns.
Funnily enough the engine's editor DeEdit Talon is more limited and glitchy than WC3 and SC1's editor. I'd play most singleplayer custom maps with cheats on, you can die too easily.
http://www.moddb.com/mods/survivalcompaign/articles
None.