You might be better off converting your AmEx points to Continental miles, then transferring to AGR and using points for a ticket. I've been doing this for trips in the Northeast Corridor, where 3000 points = 1 ticket, ~$75-85 (WAS-PHL), whereas AmEx 5,000 points = $50 Amtrak gift card. AmEx does charge a small fee for the points transfer to cover some cost they supposedly incur though (can't remember exactly how much it is, sorry).