The options are vast it all depends on your budget and how much of Florida you want to see whilst your are there.
Do you want to just see WDW or do you want to do all the theme parks, e.g. Sea World, Universal, etc? Do you want to visit the coast, for a day, for a few days? Which Coast?
For your first time to Florida 14 days or more is a must.
With an unlimited budget I would choose to book an all inclusive package deal, staying on Disney. However, I could be wrong but unless you stay in DVC accommodation most rooms on Disney sleep 4 people.
Doing a DIY holiday is not difficult and if the budget is limited then booking everything yourself is the best option. You will find lots of recommendations for best fight prices, car hire, theme park tickets and accomodation on this forum to help you.
In- direct flights often work out cheaper, also so does flying on midweek days and days just either side of a school holiday.
Fly drives can appear to be a good option but check out the insurance costs for the car hire as this can bump the price up. We always find booking our own car hire to be the cheapest option.
Mixing an onsite and off site option will give you a taste of both worlds (no pun intended).
Staying off site in a villa is one of the cheapest accommodation options, but you will need a car.
I would get a quote for a package deal and then price up DIY, the options are vast.
I always find September to be a good time to go, you can get some good deals on flights and accommodation, the parks are always very quiet, the weather is still hot, although you will see some rain in the afternoons.