What I've found is that if you try a multi-city trip and put in trip times that Amtrak won't guarantee, it looks at first like you can do it, but once you get to the pricing screen it will get kicked out as something that can't be ticketed (although it doesn't explicitly tell you why.)No, in most cases the info is not readily available from the time table. A good rule of thumb is to see if there is more than one hour between the connecting trains or not. If less, odds are that it will not be guaranteed.
The best way to find out for sure is to either call Amtrak or go to the online booking site and enter your starting and ending destinations. If the route you want is displayed, then it is a guaranteed connection. Do not use the Multi-City function however, as some connections that are displayed there may not be guaranteed.
If it is an Amtrak train to a dedicated Amtrak Thruway bus connection that is true. However, if it's an Amtrak train connecting to a Greyhound to Pudunkville departing from the Greyhound Terminal (even if it is inside the same building), that is not true!There are guaranteed train connections and guaranteed bus connections.
If your train is late, you might miss the outbound train.
But for bus connections, the bus will wait.