Non-interstate routes from Boston to Indy?

What are some good routes to take from Boston to Indianapolis. Each of the past three years, my girlfriend and I have driven out on Memorial Day weekend to see the Indy 500 with her mother and stepfather. We have stuck to the interstates in the past, but this year it might be nice to get off the beaten path and make the trip a little more interesting.

This past year we took a detour up to Chicago and Madison, WI. I lived in Madison for a summer and I wanted to show my girlfriend why I liked that place so much.

I'd like to make the trip to Indy in 3 days probably. In the past we have done the drive in no more than 2 days and a couple of times we did the drive in a single swoop of 16 hours driving.

You might work your way over to Scranton, then take US11 down along the rivers to Harrisburg. From there, drop down to Gettysburg and go west on US30 toward Somerset, then south down to US50 in West Virgina, taking it west into Ohio. I always find Ohio a bit on the boring side, but I'm thinking that the southern part of the state may be hillier and more interesting. I'd take US50 west until it splits from Ohio 32, and then take 32 (or follow one of the river roads) from there to Cincinnati and on into Indy from there.

On the Eastern leg, consider MA 23 (Woronoco to Great Barrington) through NY 23. Nice scenery, not much traffic. Best accessed from the Westfield exit off MassPike (exit 3). In NY, this goes by the Catskill Mts.

I-88 in NY runs through some nice country as well, and links to the new(er) Southern Tier Expressway, I-86 (formerly NY 17).