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

But what to do? We can't just get rid of their spellcasters!

then like this:
1. Gnolls or Flying Snakes
2. Lizard Archers
3. Lizard Warriors
4. Spellcasters
then you need 3 large units
5. Basilisks
6. Hydras
7. Tyrannosaurs
but it's better to replace the Hydras with a flying unit or give someone the ability to destroy walls.