I had a german professor once remark to me about how different Americans are, like hundreds of miles is a day trip, hundreds of miles is a week long trip by car. Bet the trains are awesome though. Amtrak long distances seems way too expensive relative to my other options when factoring in time.
Your professor said it the best way possible. I'll remember that saying to help explain it all in the future if needed to others.
I had a professor who loved Amtrak and would talk about his travels every month or so. He mentioned the price too as an issue. I definitely want to experience a train ride on Amtrak one day on an overnight trip.
A 1000 mile radius does cover a chunk of the US. Centered on Denver it covers basically everything west of Michigan (excl Alaska and Hawaii of course).