Not that mods should be historically accurate, but I do like the concept behind this mod and there is historical precedence, and the two could fit together wonderfully.

My thoughts regarding scouts and roads:

Well, first, regarding this mod, Military Engineers can create roads and railroads, this is allowing the same with no tradeoffs.

It isn't unknown for scouts to map a route (Louis and Clark mapping out the Oregon Trail), but the laying down of the roads is still traditionally done by traders, or again, later, by military engineers.

Before Military Engineers were a thing however, it isn't unknown, to my knowledge, for scouts to be responsible for making an impromptu road, especially for military campaigns to attack a neighbor. Scouts were hipster military engineers. That said, it wasn't their primary responsibility and they naturally wouldn't have all the perfections and improvements that are learned by and taught to Military Engineers.

So regarding this mod, or a similar mod with this function; scouts can make roads consuming a charge (3-5 charges total), but the road they lay down is limited to the most basic road.

Scouts would be able to do the impromptu laying down of roads for military campaigns, up until your civ really reaches the point of getting Military Engineers, who can go do a proper job of it, or making them railroads, or whatever.

It'd still achieve the intent behind the mod, allowing recon units to lay some roads, but there is a tradeoff and it doesn't replace the Military Engineer.