I found last September that I could beat the train to Sublette quite easily from Big Horn, which surprised me. We shot the train right there on the long approach, from on the wye, then passing through Big Horn at the wye, before we packed up and headed west. We were in Sublette in plenty of time to get the train arriving and departing.
Later that day we got the EB after it left Sublette at the 305 curve.
Surprisingly the sun was inside out and not bad, and the engine was working a little. This made sense cause most of the WB shots I had done in the past were kinda trundley since the engine wasn't working.
There are a few nice looking locations between Big Horn and Sublette,
but you can probably only do one of them on a regular passenger train, and if you shoot at Big Horn you need time to catch-up.
I would think a ticket to ride the special would be your best bet, cause you will save on gas, guesswork, and wear and tear on both the vehicle and you piece of mind!!!
Greg