Drivers license with International license?

You must bring your state driver license. They won't rent the car to you if you don't. You also bring your Int'l Permit (it's merely a translation of your state license), in case the rental company asks for it (they may not) or in case you are stopped by traffic police.

Often, car rental agencies have age minimums and maximums

The IDP is clear that it is not valid without your state-issued drivers license. It has no authority of its own.

Thank you very much! We'll make sure we have it along.