A half mile south of I-65, the Madison State Road turns due east on County Road 650 North/Tannehill Road towards Taylorsville. The road then turned south on either Tecumseh Street or Main Street. It sounds like the auto tour books had traffic turn right onto Tecumseh Street which followed a section line most likely down to County Road 600 North where traffic would again turn east back to the railroad tracks where it would follow the railroad southeast into Columbus. Since Tecumseh no longer goes through, you should turn left onto Friendship Drive which curves over to the railroad tracks. Notice the very wide bridge just before Friendship Drive turns back west to meet US-31 at County Road 600 North. The width of the bridge indicates that at one point Friendship Drive was part of the Madison State Road alignment.
A little bit south of County Road 400 North, you can turn left onto Indianapolis Road to head toward downtown Columbus. This road was formerly IN-11 and before that, Alternate US-31. This is the best route to downtown Columbus, as US-31 bypasses it to the north and east.