What you need is to copy the following files and folders into RTW\Data directory:
models_strat
terrain
text
UI
world
descr_rebel_factions.txt
descr_sm_resources.txt
rebel_faction_descr_enums.txt
And edit descr_strat.txt to delete 'win_conditions' entries, add spawn values for brigands and pirates, and modify diplomacy sections.
Also don't forget to copy the following files to mundus_magnus folder:
leader_pic_romans_brutii.tga
leader_pic_romans_julii.tga
leader_pic_romans_scipii.tga
map_gauls.tga
map_germans.tga
map_greek_cities.tga
map_romans_brutii.tga
map_romans_julii.tga
map_romans_scipii.tga (but of course you can use alternative tgas...)
descr_win_conditions.txt
description_romans_brutii.txt
description_romans_julii.txt
description_romans_scipii.txt
Hope this helps... :wink: