Trade is arguably the most powerful aspect of Civ2 for the human player. The AI is rather poor at it. I am not sure what you mean by optimal.
I am not much into scenarios. But the two that shipped with the game, and all others that I have seen concentrate on war. Some, like the one I am playing right now in GOTM 167, go as far as disallowing trade. If someone knows of a trade oriented scenario, I too would be interested.