Comparable. The big difference with Stanford is that they are on a quarter system.So the workload is high per class, but,on average, you take fewer classes per term.
As many as it takes. The rule of thumb is that for every hour of class you will spend 2-3 hours of studying/prep time. But this will vary by class and instructor. The grapevine at the college (or an official/unofficial guide) will give a new student a better idea on specifics.
All this is moot, of course, until one gets accepted, so that should be your focus.