Check autoslash and costcotravel if you are a member.
And check
Enterprise, a lot.
Don't book anything unchangeable.
Make sure you have unlimited mileage.
And read EVERYTHING about the rental to make sure there are no restrictions on where you can take it. If everything goes fine then they would never know, but if you got into an accident in Florida and it turns out you weren't supposed to be in Florida with the rental, it will not be good.