Just for comparison, I made a table of Amtrak stops between Kankakee, and Carbondale, Illinois, with the distance in miles and the populations of the towns/counties served, and the same for the Empire Builder between Fargo and... , to show the difference in the sizes and distances of the towns.
Kankanee City (24,000) County (110,000)
28 Miles
Gilman (1700) (29,000)
36 Miles
Rantoul (13,000) (205,000)
16 Miles
Champaign-Urbana Together= (116,000), (205,000)
48 Miles
Matoon (17,000), (47,000)
28 Miles
Effingham (12,000), (34,000)
60 Miles
Centralia (12,000), (37,000)
40 Miles
Du Quoin (5800), (21,000)
20 Miles
Carbondale (22,000), (53,000)
So in this 280 miles after the train has left the Chicago area, it serves towns with a population of about 240,000 people, and counties with a population of 510,000 people. I don't know if the half a million people across those counties can all easily reach the train station, but also there might be people outside of those counties that can.
So lets look at the same thing, from Fargo westward on the Empire Builder.
Fargo, North Dakota City (126,000), County (185,000)
80 Miles
Grand Forks (59,000), (73,000)
90 Miles
Devils Lake (7,000), (11,000)
60 Miles
Rugby (3,000), (4,000)
65 Miles
Minot (50,000), (70,000)
55 Miles
Stanley (1500), (10,000)
70 Miles
Williston (30,000), (40,000)
95 Miles
Wolf Point, Montana (2500), (10,000)
50 Miles
Glasgow (3,000), (7,500)
70 Miles
Malta (2,000), (4,000)
90 Miles
Havre (9,000), (16,000)
100 miles
Shelby (3,000), (5,000)
60 Miles
Browning (1,000), (14,000)
90 Miles (I am leaving out the GNP stops because they aren't really towns)
Whitefish (8,000), (100,000)
In 420 miles, the Empire Builder in North Dakota goes through cities with a population of around 280,000 people, and counties of around 390,000 people. In 460 miles in Montana (I am ending in Whitefish because Flathead County is the first county with more than 100,000 people after Fargo), the Empire Builder goes through towns with about 27,000 people and counties with about 160,000 people, and 2/3rds of those are in Flathead County (Kalispell and Whitefish). Together, in about 980 miles, counties with a population of about 550,000 people are served, and about half of that population is in Cass and Flathead Counties, almost 1,000 miles apart. One county served in Illinois (Champaign) has more population than all the counties served in Montana.
I might have made some slight errors in math, I used google maps to calculate mileage based on roads, which isn't the same as the rail routes. There are simplifications in how I calculated things, but hopefully these numbers communicate a little bit of the difference in scale between what a "rural" route means east of the Mississippi and in the Great Plains/Rocky Mountains.
And I should probably find a better way to spend my Sunday.