there are two things you have to do disabandon team rocket and battle the red gyarodos
Between Mahogany Town and Lake of Rage.
East of mahogany town.
Mahogany town.
the next gym is @ Mahogany Town
There IS no Radio Tower in Mahogany town
TM46 Thief can be found in the Rocket Hideout in Mahogany Town.
Get the seven gym badges, run Team Rocket out of Mahogany Town and Goldenrod City then go back through and you should be able to go past.
in mahogany town in a house beside the gym
You can find TM Thief in Mahogany Town in the Rocket Hideout
go to etacreack city and on the right side u can find the town
The 7th badge/gym is in Mahogany Town. The Gym Leader mainly has ice type pokemon.
Go east from mahogany town, go through the Ice path, and you will be in blackthorn.