I did a similar trip across Canada last year.
Ottowa to Toronto
Toronto to Jasper (3 days, 2 nights on sleeper)
Jasper to Prince George
Prince George to Prince Rupert.
You need to enjoy travelling! The VIA Rail sleepers although rather tired and cramped, are clean and are as comfortable as you could expect in sunch a confined space. Each compartment has two easy chairs which are stowed away at night to make way for 2 single bunk beds. You've your own loo and sink, but there is only one shower at the end of each car. We spent very little time in the compartment, except for sleeping, spending the majority of time in one of the many observation dome cars... or eating! The restaurant food was superb.
I think it was 4 or 5 time zones that we crossed during the journey.
The scenery was, as you'd expect, breathtaking, however it was split into 3 distinctive bands. The Canadian Shield which was just Lakes and Trees, The Prairies, and the Rockies. We went in Spring, which according to many, is the best time to go....... The snow melt was still fuelling the rivers, and the predators such as bears had only recently come out of hibernation and we saw dozens of them in all, all searching for food.
If your USA trip is only half as good, you'll enjoy it!
The only down side was the tax and tipping policy.

All prices in restaurants and bars were minus tax.....
You'd to add VAT, then a seperate local state tax, and to cap it all, tipping was expected at around 15%.
Virtual Navvy for North West England & Metrolink.
Two rules to get you through life: If it's stuck and it's not supposed to be, WD-40 it. If it's not stuck and it's supposed to be, gorilla glue it.