in 1798 at the end of the Wilderness Road at  Louisville was there a road people with wagons would take to reach southern Illinois?

yancey, if the city has its own historian, that's where I'd start looking for my answer. (Unfortunately, there's a quarterly publication named "The Historian" which makes an internet search futile.)

If you can't find a historian, consider contacting https://filsonhistorical.org/

It was not a "Road" it was more like a trail.

I have a photocopy of a diary written in 1854 of the journey made by wagon and the reality was there were very few 'roads' most 'roads' were just worn dirt tracks joined by marsh land, forests and generally uncultured land.... one part of the diary discribes  it taking 11 hours to travel with the wagon about 2 miles across  the marshy land and one guy walked the 2 miles back to the last camp to collect the fire wood left there so they could build a fire at their new encampment..The USA was in the main a wilderness with very few dirt 'roads' in some places