Darrin, I have just the solution for you. Subscribe to my mag at the link below, and you'll get it all, man.
Seriously, asking questions like that can be perceived as bad etiquette. But the problem with that question is that there isn't a perfect answer. We all want a place that has low hunter density, high elk density, high mature bull density, and terrain that is nice and easy. It just doesn't work that way, as far as OTC tags go.
You have to set priorities as to what you want: get away from other hunters? a particular landscape you like to hunt (north woods like N. Idaho or desert)? Absolute success at notching your tag? Decent chance at a 6x6? There's give or take in all of it. There isn't the perfect general season elk zone. Can't have it all.
So, ultimately, the question you asked just doesn't make much sense. What are some of the best areas to hunt OTC in Idaho?
IT DEPENDS.