I am a vet tech, and here's what I would tell you if you were one of my clients.
If you buy the Advantix (not Advantage) through a veterinary clinic, it is 100% guaranteed by Bayer to repel ticks and mosquitos and kill all stages of the flea life cycle.
I would start applying it monthly now. Make sure you part the fur and apply the product directly to the skin. In larger dogs you can apply it down the spine.
If you plan to bathe your dog it's best to do so either 2 days before or 2 days after an application, as the skin does need to be a little oily to absorb the product. It is waterproof however.
You do not need to, nor should you use any other product on your dog. No collars, pills, sprays etc.
That being said, you may find a tick walking on your dogs fur from time to time, but it will not be able to attach or bite, and therefore unlikely to transmit disease.
Keep in mind that these pests (fleas, ticks and mosquitos) love the warmth and hunidity of Florida. Your pet should be fine if you keep up the Advantic during your trip.
One last bit of advice...consider microchipping your dog if you haven't already done so. It's the only way to permanetly identify your dog as belonging to you if he/she should get lost.