Amtrak has decided to annul the Starlight completely through 1/31 (so far). It's highly unlikely they would run it via the Oregon Trunk, especially on a recurring basis, because of the line's lack of capacity (especially if there are detouring UP trains), the need for pilots, and Hours of Service considerations. It's no so much the extra 100 miles as it is the likelihood of spending a lot of time stopped for meets, etc. Too bad, it would be a swell ride.