1-The plan was for us to get there.
2-The plan was that we should get there.
Do these mean:
a-The goal of the plan was for us to get there. The plan was devised in order to make our getting there possible.
b-The plan consisted of our getting there. Our getting there was the plan itself. Its goal was something else.
It seems to me that '1' is ambiguous but '2' means 'b'.
I agree with you that '2' unambiguously means 'b'.
I also agree that '1' is a little bit ambiguous, but that's how most people would say it, when they mean 'b'.
I'm not a teacher of English, but I have spoken it for (almost) all of my life....