WE live in Central Tennessee, and in the last year twice traveled I65, to Gary and to I69 in Port Huron. I do not remember any bad sections. There was some construction on I69 around Fort Wayne area, but it was in a rural area. We have traveled both ways may times over the last 30 years, and prefer I65 to I69, even though it is longer to get to Canada where we have family. Less traffic and major cities to go though.
Where are you headed too? The only mountain that I know of near Chattanooga is on I24 at Mount Eagle, which I have also traveled a lot.