NX4.
Please see attached document for details.
I intend to create a sequence for a presentation. Although Motion Application is available, I have no experience of using it, I thought this would be a quicker solution.
You can use Insert> Trim> Join Face to make a single face from the individual flat and cylindrical faces of the slot walls. Use only the walls needed to complete the path. Then you can mate your rollers to the slot walls using the Tangent mating condition.