Right, I was going to book two one-way tickets to avoid this! I know the first trip would be "low risk" but the return (train then flight from EWR to BNA) would be the medium risk. And was curious what this would actually look like... if I could just download the Amtrak & United boarding pass/ticket via mobile apps, or should I go to NYPenn to the Amtrak window to pick up the Amtrak ticket (even though I wouldn't actually ride/use it) etc.