After coming up I-65 and US 31 to Elkhart this week, I would suggest you not drive in Indiana. This state has, by far, the worst roads of any state we have been in. There was a news segment the other night about how Purdue University was researching how to make Indiana roads better - most states figured this out years ago so that should give you some idea.
I-65 from Scottsboro north to Indy to Franklin can be tough. There is road and bridge construction in this area and some single lane. Other than being rough and full of pot holes and poor bridge transitions, traffic wise wasn't too bad.
I-465 - East from the junction of I-65. Under construction and quite rough in areas.
I-69 - pretty good
US 31 - no traffic but some road construction in Carmel. Condition of road depends on county you are in. Best section is around Kokomo.