The 2 times we drove from Chicago (never again! lol), we went both ways: I-65 & I-57. We thought I-57 was better with snow removal, but you won't have to worry about that driving in June.
The drive through Illinois and Indiana are both boring, so I don't think it really matters! lol.
Congrats on your wedding!
Oh, and when we drove the last time (years ago), I went on McDonalds website and it has a map feature on it. You put in your destination and it lists all of the playlands along your route. It comes in handy when you have small kids who have been sitting in car seats for hours. Though, once you get south of Kentucky, we noticed the playlands were all outdoors.
If I can find my travel info from our drives, I'll post back on where we stayed in Chattanooga. We had 2 great hotels we stayed at. One was a inexpensive one-bedroom suite. This was in a business district with more conference-style hotels. It had a pool, and the room had lots of space, so it worked for us. The other one was near the housing districts. Affordable family-style restaurants within walking distance. It had a pool, too.
HTH