Ah, I think I know what you mean. Head up Mt. Chimney, then down Jagged Pass. Somewhere along the way, you will find an opening. Be prepared, as this is Team Magma's base. After that, it resumes as it normally does in Ru/Sa.
Oh, and there is another thing coming up (it's different from Ru/Sa) that'll confuse you. If you need help with that, PM me.