Both calculations below are calculated at 6% interest rate, which is bound to go up in the coming years.
If you do a 10 year repayment plan for IU, you will spend $40,000 a year on repayment for 10 years, total interest will be 150,000. Probably could even pay that off sooner if you up your payment.
If you go to Louisville out of state (based on $400K total COA), you will spend $64,000 a year for 10 years, total interest will be $240,000.
You will come out of school making between $100,000-$120,000 pre tax, so say 70K-90K yearly salary depending on where you are in the US, and most likely won't go up too much as an associate. Subtract rent, malpractice in, disability in, potential car payment, living expenses, possible spouse or kids depending on what that looks like for your life, and you're really tight on the Louisville budget for a decade and it's not going to be fun. Factor in a loan for buying a private practice loan to really make a dent in that Louisville debt.
If you do REPAYE get ready for that tax bomb at the end, and hope the current administration doesn't throw that program out.