I was strolling through the grass in Viridian Forest and I actually ran into a Pidgeotto! Then I thought to myself "how hard would it be to beat yellow using Ash's Pokemon and beat the gyms in the order he did" Super hard but if you are devoted pretty awesome.
Pokemon you can useikachu,Caterpie,Metapod,Butterfree,Pidgeotto,Bulbasaur,Charmander,Charmeleon,Charizard,Squirtle,Muk, Tauros,Krabby, and Primeape.
Ash never caught Haunter so not allowed.
You must release Butterfree after Lt. Surge.
Don't forget to skip over Erika and Koga to fight Sabrina.
Primeape,Krabby,Muk and Tauros should be used sparingly since Ash didn't really battle with them that much.
If you want to do it right only Pikachu against Brock and Lt. Surge.
Post any ideas in the comments.
Took me Forever