You don't. You cannot re-enter Mt Moon until later in the game.
Go to pewter city then head right. If you see about 8 trainers you're in route 3. Just go left. Then up if you see one guy that is not a trainer. In route 4 you can see Mt. moon. After you pass to Mt. Moon then you are in Route 4 ( continuation ) go left and you will be in Cerulean City. ( If you want to go to route 4 Fly to Pewter City and repeat the steps I did ) If you don't understand this please improve it. Thank you.
its near the northwest corner of the route.
Red is not in Mt. Moon; he is at the top of Mt. Silver.
Blue Shard- Route 124; Wild Pokemon. Green Shard- Route 126; Wild Relicanth. Red Shard- Route 124; Wild Pokemon. Yellow Shard- Route 126; Wild Pokemon.
You can find a few on route 3.
on route 227???
its near the northwest corner of the route.
Go to pewter city then head right. If you see about 8 trainers you're in route 3. Just go left. Then up if you see one guy that is not a trainer. In route 4 you can see Mt. moon. After you pass to Mt. Moon then you are in Route 4 ( continuation ) go left and you will be in Cerulean City. ( If you want to go to route 4 Fly to Pewter City and repeat the steps I did ) If you don't understand this please improve it. Thank you.
Pewter.
I used a Nidoking to beat the third gym leader and you can find a nidoran male on the route you get the running shoes on and a moon stone in Mt. moon
Red is not in Mt. Moon; he is at the top of Mt. Silver.
Northeast of Cerulean City.
Blue Shard- Route 124; Wild Pokemon. Green Shard- Route 126; Wild Relicanth. Red Shard- Route 124; Wild Pokemon. Yellow Shard- Route 126; Wild Pokemon.
Route 2 is north from Viridian city.
Drowsee is uncommon in route 11.
Walk in the grass by route 5-8.
You can find a few on route 3.