Getting through Kanto can be a little confusing, so here's the path:
Start at Pallet Town
Go through Route 1
Arrive at Viridian City
Go through Route 2
Go through Viridan Forest
Arrive at Pewter City
Go through Route 3
Go through Mt. Moon
Go through Route 4
Arrive at Cerulean City
Go through Route 24 and Return to Cerulean City
Go to Route 5
Go through a connecting tunnel to Route 6
Arrive at Vermillion City (Obtain Cut on S.S. Anne)
Go through Route 11
Go through Diglett's Cave
Go through at Route 2 (Obtain Flash--Need 10 Pokemon owned)
Go through Viridian Forest
Arrive at Pewter City
Go through Route 3
Go through Mt. Moon
Go through Route 4
Arrive at Cerulean City
Go through Route 9
Go through Route 10
Go through Rock Tunnel
Continue through Route 10
Arrive at Lavender Town (Obtain Pokeflute)
Go to Route 8
Go through a connecting tunnel to Route 7
Arrive at Celadon City (Obtain drinks--Now able to access Saffron City)
Go through Route 16 (Obtain Fly)
Go through Cycling Road (Need Bike--Fly back to Cerulean City)
Go through Route 18
Arrive at Fuchsia City (Obtain Strength and Surf)
Fly back to Saffron City (if not already battled after Celadon)
Go to Cinnabar--Routes 19, 20, Seafoam Islands, continue through 20 (South of Fuchsia) OR Route 21 (South of Pallet Town)
Fly back to Viridian
Go through Route 22
Go through Reception Gate
Go through Victory Road
Go through Route 23
Arrive at Indigo Plateau
This isn't set in stone of course; just make sure you have the HMs necessary to get through whichever route you intend to!
((will prettify later))
