This link might be helpful. Indiana Traveler Information
I have driven US 31 from Indianapolis northbound (and returned) several times. It is good 4-lane highway, with the usual stop N go for congested areas, like Kokomo. Outside populated areas, traffic was light and steady. There are a few truck stops along the highway, which makes traveling with an RV convenient. Road construction/rebuilding seems to be a ongoing project, but does not cause problems for travelers.
I've driven US 31 and I 69 traveling to Goshen, I 69 seems faster than driving US 31, but I suppose that's because of driving 55 MPH on US 31 vs 65 MPH on I 69 with no towns or stoplights to slow you.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"