Originally Posted by
mkraft
Also, re: "Sometimes," is there a way of knowing in advance whether a V###-coded ticket will be accepted (for intermediate station embarking/disembarking)? Does the offer have to explicitly state that, or can it be assumed to be allowed if not explicitly prohibited?
Trial and error. If the discount code can be used in conjunction with an online booking, try it for your desired city pair and see if it works; if the code cannot be used online, call Amtrak and see if the code will be accepted for your desired city pair.
Note: there are some discount offers that, rather than being valid to or from a particular city, are valid over the length of an entire route. Currently, there is a 20% discount code valid on Empire Service and the Adirondack in New York State, valid for travel between any two cities served by these routes.