RTF is a global modification that replaces all towns in the game.

By the way, maybe give Trogolodites to the Mountain Orcs?

Trogolodites are already planned for the Dark Gnomes.
Approximate Orc lineup:
1) Goblins - ranged units
2) Orcs - melee units
3) Orcs - melee units
4) Centaurs - ? (melee or ranged)
5) Trolls - melee units
6) Ogres - melee units (Panther Warriors from Heroes 6)
7) Black Wyverns - flying, melee units

Added after 32 seconds

Levels 2 and 3 - different units.