There is so much that goes into training beyond a predetermined scenario, especially if you want any kind of learning to be achieved. When I do outreach it is very different from in the metro area or if I'm out in the mountains or plains working with rural services. Are you just teaching the basics or do you want critical thinking (or said other wise, are you teaching to the protocol or outside of it)? What is the provider level, and how engaged are they in continuing education? Are you evaluating outcomes, if so how are you going to evaluate?
Even withing drownings there can be vastly different presentations. Down time, wet vs dry (and this isn't as clear cut as people used to think), individual pathophysiological changes, et cetera make a huge difference.
As a side bar, what is your plan for addressing rescue? Most EMS agencies prohibit their members from engaging in hazardous rescue, are you going to teach against this policy? Are you going to wait for fire? What if fire needs to wait for a particular rescue unit?