Jane, you are right in that July and Aug. are pretty hot. We won't be there in the summer unless we juggle some other plans, but won't know this soon.
Southwest flies non-stop from Indy and we use them because if your plans change they do not charge to change the ticket. (unless the new date is a higher rate)
You can go to any hotels web site and get their 800 numbers. Most will have lower rates than are posted. It is usually cheaper to book your flight and rooms independant of each other.