You cannot prepare for gym leaders because you don't know what Pokémon they have.

Extract the file if it arrives in a zipped archive ( .zip or .rar ). Ensure the file extension is strictly .nds . Step 2: Download the Universal Pokemon Randomizer

This removes the necessity of carrying specific "HM Slaves" by letting any Pokémon potentially learn crucial field moves like Cut, Surf, or Rock Smash. If you want to customize your setup further, let me know:

Classic Pokémon games offer incredible nostalgia, but replaying them with the exact same encounters can become predictable. If you know exactly which Pokémon appears on Route 201, the magic of exploration fades.

Enable "Fastest Text" or "Remove Trade Evolutions" so you can evolve Pokémon like Machoke through leveling instead.