Bloomington is conveniently located in the middle of the Middle. That is to say, it's driveable from most of the Midwest, and quiet a lovely drive at that. Here's the route we suggest based on where you're coming from.
From the North:
Coming from Indianapolis and points north, the best route is State Road 37. This route does have several stoplights and exits to neighboring towns, but it's relatively quick trip. A similar route is State Road 67 which connects with State Road 37 in Martinsville, and it is also the best route to and from the Indianapolis International Airport.
Note: State Road 37 is under construction and will one day become Interstate 69. So eventually, it will be a very speedy and efficient route. For the next several months, it will be slower and congested with construction traffic.
From the South:
State Road 37 takes you directly into Bloomington, and it connects with Interstate 69 just a few miles south of Bloomington. Coming from Louisville or points southeast of Bloomington, I-65 is a good option, and connects with State Road 46 in Columbus, IN which takes you on a scenic drive to Bloomington.
From the East:
As mentioned, State Road 46 is the best way into Bloomington, and very scenic. It is a winding, hilly route between Bloomington and Nashville, IN, so just know that you might be driving the max speed limit the entire way, especially if you get behind a slower vehicle. Just slow down and enjoy the views. State Road 45 also winds through Brown County and into Bloomington, but is even more winding and a little slower.
From the West:
Both State Road 46 and 45 will bring visitors to Bloomington from the west. State Road 45 heads slightly south, while 46 heads a bit north, so most visitors will connect with 46 first, particularly if you take State Road 231 south from I-70. State Road 46 is a pretty route, and goes through several smaller communities before you hit Bloomington.