Replying to Training for the season

I'm planning a trip this winter to steamboat and I'm looking to train really hard so I have a good season. I'm going to try to make the best out of going out west, being from the Midwest. I'm planning on progressing all my tricks and stuff a lot and I realized I'm gonna have to get a lot stronger just so I am more controled. I'm in really good shape because I run cross country but I need some more muscular strength. I'm a strong guy overall but does anyone know exactly what muscles I should work and stuff? I'm assuming a lot of core?