use action replay to go through the walls. no trainers will battle you. use the action replay code for the rare candys.go up to lvl 100[use 1 pokemon]use any moves 3 times and you get the fen badge[5th bdge in PL,4th badge in D\P].
Go to Hearthome City. Although first you have to beat Mayleen and Crasher Wake. After that you can challenge her. You don't have to beat Mayleen and Crasher Wake in Pokemon Platinum. -
crasher wake is in pastoria city
its ez
Crasher Wake is in the very back of his gym in Pastoria City. He is a user of Water-Type Pokemon.
gyarados
29 32 31
garidose,flotazel and quaza.esey pesey
talk to wake at the entrance to the great marsh
to verity lake
The fifth gym leader in Pokemon platinum is crasher wake but you get the fourth badge.
After you beat him, continue on with the game. I think you run into Barry after you beat him, or it might be before..
He is in Pastoria City. Hope that helps a little bit.:)