Tim, the Rally Fee allows you to attend all functions at the campground. Trips outside the campground, like the Amish Dinner or visits to Museums are extra. The exception to external trip fees last year were:
Montana Factory Tour
Ladies Driving School
The above list is predicated on the belief these events will take place. As far as I know (which isn't much past my nose), no events have been set in stone yet. Please keep an eye on the Fall Rally section for up dates and sign-ups for various functions.
And be prepared to have a good time!