The drive from Indianapolis to NYC is nearly 12 hours (not including breaks) by car. You're looking at 17 to 20 hours by Greyhound. That sounds absolutely miserable to me.
I would look into flights first. If you can get something reasonable it's well worth the money. I was on a greyhound for about 7 hours once when my connecting flight got cancelled because of snow and no rental cars were available so they gave us a free greyhound bus ticket. By far the most mmiserable traveling experience I've ever had was being on that bus. Never again.
This is one of the occasions when hunting out a travel agent or travel group in your area might be best. They might have some sort of package or group deal set up for New York City.