Let's play Pokemon Yellow Legacy Pikachu only run part 2

Thumbnail made by my brother.
In this part I go through the rest of Route 2 and entering Viridian forest, to then entering and battling Brock the gym leader. I will mostly train and level up Pikachu off camera so I won't waste anyone's time and seeing me grind.
My goal in this fight is to get Pikachu to larn Tail whip, so that when I fight the trainer and Brock. I have means to lowering their Defense stats so that Pikachu's Quick attack will be able to deal damage, hopefully enough damage to win the battle and gym badge. A tough road block considering Geodude and Onix are RockGround types. I can't use Thundeshock at all. Let alone they too resist normal type attacks.
Although...uhh, I have NO IDEA what the heck happen to Brocks A.I during the fight...he kept...spammign the same move near the end XD.