They would like IOA the most if they like roller coasters.
If you're spending 2 weeks in Disney, you midas well plan for 3 days at USF/IOA. The best ticket deals are usually the 2 days with a 3rd day free. Or you could also think about visiting Sea World Florida (SWF) for a couple days. They usually have a buy one, get the 2nd day free.
The thing about it, is you don't have to spend an entire day at each park. You can visit one in the morning, then go back to your hotel to rest, then visit Disney at night since they stay open late.
You could visit IOA one morning, Disney at night.
Then USF the next morning, Disney at night.
SWF one mornng, Disney at night. You get the idea, it's not like you're losing a bunch of Disney days.
Visiting SWF is easy to do, because you can catch the #50 Lynx bus from the TTC for a couple bucks a person.
http://www.golynx.com/
As for driving up to IOA, you either rent the car for a few days, or use a limo service. I'd look into renting the car for a few days. The convience factor makes up for the gas and parking fees you will pay.
