I will be on the Empire Builder next Wednesday in coach all the way to Seattle. I did the same trip over Christmas in coach for the first time.
The two day ride is long. Bathrooms are hit and miss, depends on how many disgusting people happen to be on your train. I had decent crews, but our trains were overbooked and the bathrooms got shabby on my outbound leg.
To me riding coach is rather like camping. You won't get as good a night rest as your own bed, you have to sponge-bathe, you have to make do without TV or an Internet connection. But, much like camping, you can meet all kinds of characters and hear their stories (for example - I met Amish people on both my EB trips, interesting and not what I expected), read books you don't otherwise have time to, and zone out looking at the scenery.
I plan to get near an outlet so I can do some work on the laptop. There are also some good Amtrak tips out there: This trip I am including ear-plugs, a sleeping mask, water, Tylenol PM or booze, and wet-wipes. Bring a blanket.