I've done this trip in reverse, and while it was beautiful and grand for the first 2/3ds, it was dark and dank for the last bit.
These trains definitely don't arrive on time, BTW, from what I was told...
Still, I wouldn't discourage anyone from doing it. Train travel is fun and communal, after all, and you get to meet people while enjoying beautiful scenery.
Thanks for the report KW ^ :-: