When we travelled on Amtrak with our children many years ago, we used the passes frequently. The best part was the ability to add multiple segments and not return via the same route. That is why I suggested to you that your Segment 7 would not be permitted, as "retracing" the same route on the same train was definitely prohibited "back in the day". I was glad and surprised when you pulled it off. The workaround that was possible a long time ago was to take the Zephyr to SLC and transfer to The Pioneer to Portland. It sounds like you have a great trip planned, although don't rule out the occasional upgrade of a segment to Business Class or sleeper if funds permit.