I'm 90% certain the roads just get bigger. Same design reproduced at multiple sizes.

You may not be interested any longer or might already have gotten your answer, but I believe the roads are printed in proportion to the size of the rug. Meaning, the roads are the same width & the pattern is exactly the same no matter the size. So, there aren't more roads or larger roads. Hope this helps.

Not sure how helpful this is, but we have a blue stripe in our nursery that is the official University of Illinois color of blue paint, and it very closely matches the darker blue color on the rug.

From The Land of Nod paint selections given, I would say either Weatherman blue or The Sky Blue Sky blue would be safe choices. The Growth Chart is the most difficult to match, but since it won't be the primary focus of the room(the bedding and rug will be) I think you should ask for samples, if possible, to see which of the blues works best in the room being decorated. Remember that lighting & current wall color affects the actual shade of color & may result in a different effect than what you're desiring. So, take this into account when choosing your blue hue. I would suggest sticking to a blue with a grey hue in it. The blues themselves have grey in them, & red & black compliment the grey-blue hue well. Hope this helps!