Player2 on 02 October 2012
Played through crystal recently, and for the fourth gym I used a Fearow (see NinPie, it is useful). Since it's part normal is inmune to ghost attacks, and flying moves hit ghosts that have usually low physical defense.
Edit - Totodile learns Bite at level 13 and Crunch later, he should make the forth gym a walk in the park.
