Press F4 on the GUI, the title will switch to Stealth Quester (debug mode), this can be used to disable banking/grand exchange. It requires you to have same items in inventory/be at same position as when it was interrupted. It's supported on MOST quests but still not all cases. (There is also an iron man mode on F5)
Also if you encounter many problems, make sure you start a fresh client when running the quester, not in lowcpu mode. There may be other scripts that are still running background tasks due to some messed up code, a fresh start would make sure it's running at it's maximum potential.