There are three regions to consider when you're using points to book a trip. Each time you move into a new region or zone as AGR calls it, you have to use more points to complete your trip. For example, I live in NY City the eastern zone. If I wanted to travel to Florida, also in the eastern zone, I'd need 15,000 points to get a roomette. If I wanted to travel to California, since I'm now crossing two zones that same roomette would now cost me 35,000 points. You can view the map of the zones by clicking
here. Note that the NE zone only applies if one is traveling solely within that zone, otherwise just use the eastern zone for all other travel on the east coast, even if you start, end, or pass through the NE zone.
Segment and leg are essentially the same thing, it refers to one train or bus. Returning to the example I used above, if I go from NYC to LA via the LSL and the Chief, I'll have a two segment trip. That being the LSL and the Chief. However, if I were to make that same trip using the Capitol Limited instead of the LSL, I'll now have a three leg or three segment trip. I'll get one ticket to ride a Regional from NY to DC, another ticket to ride the Capitol to Chicago from DC, and a third for the Chief from Chicago to LA.
For each segment or leg that I ride, I get AGR points based upon how much money I spent. If the amount spent was less than $50, then I get 100 AGR points. Thanks to a new rule that AGR just implimented last year, if I have more than 4 segments or tickets valued at less than $50, I don't the minimum 100 points for all segments 5 and above.
Hope this helps.