First of all, the Amtrak Guest Rewards program is probably the best rewards program currently being offered, but AGR will try to restrict how far you can go on them. AGR's map strongly implies that you can go from El Paso, TX to Wolf Point, MO for 15,000, but if you try to book this passage in a sleeper they will say that it is two trips instead of one. You can only transfer one time; example Empire Builder to Pacific Coast Starlight, but in order to go to El Paso, you would need to transfer to the Sunset Ltd. Amtrak terms all of this as "Piecing a Trip Together", which they will not permit under the AGR program. So, you are not able to truly go on trips from one end to the other end of a zone of travel on Amtrak Sleepers.