Keep it under 65, turn off the cruise control, and drive with a very light foot.

At 65 w/o CC, you should hit 28. At least 27.

Cruise control hits the throttle pretty hard when your speed decreases. If you take control, you can take different action. Your actions are based on more input than just "the car slowed down". You can look ahead and see a hill before you get to it and GENTLY add 5mph before you get to it, and accept losing 5-10 mph as you climb it... then use momentum to get back to cruising speed (or a tad higher) on the other side.

You may think FL doesn't have enough hills to think that way... but it does. Even overpasses count. The more time you can spent in a completely off-throttle coast, the better your MPG will be.

Good luck!