Hey. Have you been to Florida before? I like to get a car to visit my old haunts, I stayed for 3 months in Daytona and 3 months in Vero beach doing my flight training so I like to get about.
Don't worry about getting around. If you stay on Idrive, you have a bus going up an down the strip all the time.
Universal and Wet n Wild are easily within walking distance. There are regular shuttles to Disney (just be careful, some hotels advertise a shuttle, but some only go once a day - which is not a "shuttle" in my books).
For Busch gardens Tampa, you can get a package which includes the coach. It's 1hr 30 and the busses there are a lot more comfy than here. So you can easily have a blast without a hire car. You can also chill out with a nice frozen margarita without the worry of having to drive back!
You also have regular service busses to Downtown Orlando, but to be honest there's not a lot to see there.
You will have a fantastic time. I LOVE Florida - want to live there one day. The other thing you have to worry about driving, apart from their complete lack of safety or driving ability, is the lack of MOTs there. You will see some right wrecks, especially out of the large cities!!