Definitely check the rental car company's policy for driving outside the state. Some permit only contiguous states; others will let you drive across country! Then check your auto insurance policy (call your agent) to see if it covers a rental car and to what extent. Insurance laws are different in every state. Research Florida's minimum insurance requirements on the internet to be sure you're covered. As the other poster noted, your CC may offer gap insurance.
Beyond that, look at the rates. Subscribe to the Mousesavers newsletter to get current codes. Keep in mind that they are geared to rental in Florida, rather than another state.
Also check The Entertainment Book. There usually are some decent coupons in it. Most of the coupons expire October 31, but the car rental coupons usually are valid through December 31.