Our first thought, based on what others had written, was that their stagecoach crossed the Des Plaines at the Summit Ford, stopped to change horses at the Summit stage station, then followed Archer Ave along the south side of the Des Plaines to Lockport.
Both 1822 GLO Plat maps & 1851 Reese ownership map agree that from a point about three miles south of Summit, that would have put virtually the whole route through timber (except the portion around Saganashkee Slough, which was swamp). This route from Summit Ford Stage House south was a road through timber.
“We then looked at “Joliet Road” (which later had about a 50 year period under the name “Route 66”). It follows the modern course of Joliet Road from Countryside, It then merges onto what is now I 55/The Stevenson Expressway, between I-294/Tristate Tollway and County Line Road in Burr Ridge. It follows I-55/The Stevenson all the way south to the Joliet Road South exit just past where I-355 passes over I-55.”
It is normal to change stagecoach horses every 10-15 miles. Going 25 miles is extreme. The distance from Lawton's to Joliet is 36 ½ miles. It is likely there was at least one stop to change horses, if not two. These stops were unmentioned by Eliza.