Amtrak might complicate things.
I used to be a big supporter - worked to preserve funding, etc.
But service is positively awful. They lost my bike last time. Sent it to a different place than I was going. I don't know what kind of drugs the ticket agent was doing. I mean, why would I be going to East Glacier and want my bike in Whitefish? Plus, Amtrak has horrendous on-time performance - esp. on the West Coast. The Coast Starlight was 8, 12, even 16 hours late this past summer. It was a total joke.
This past summer, I took Greyhound instead. Did someone say, "Out of the frying pan into the fire?" I feel lucky to have emerged alive from the bus. So the options aren't pleasant. Another possibility - if you haven't already bought your Amtrak ticket - is to ship your bike from a bike shop and take Southwest or another discount airline. You'd be surprised when you add the cost of food - esp. Amtrak food - that they might come out even.