Thanks again for your advice, but I am still having trouble with the flow path tool.
Below are two payblasts of what I am encountering.
This playblast shows how my object is twisting along the 'up vector'. This is what I was interpereting as banking, but it is actually the curve defining the deformed object's up vector, i think.
If I could figure out how to make it so the object didn't roll AT ALL along the path, then this wouldn't happen and I could animate the roll manually.
This playblast shows how the objects aren't staying on their respective curves. This particular segment is the most ugly, it is clearer what is happening in the third playblast.
Here you can clearly see what is causing the 'jumping around' of the previous movie. The object is deforming to the curve, but the pivot is riding the curve and lifting while the deformation isn't compensating for the rise. (make sense?)
I don't think there is anything I can do about the object appearing to 'de-rail'. It's actually sticking to the path and the deformation is pushing it off.
Is there a way to eliminate the first problem, where the lattice inverts while turning along the y axis? Can I turn off the 'roll' effect of the path?
[EDIT: I distorted the curve so that it never aims directly 'up' by moving the lower part of the curve away from the camera. It barely changes the shape of the object but brings down the twisting effect to about 15%. This qualifies as a work-around and I would prefer to not have to do it. Is there a way to 'turn off' the roll effect?]