Depending on where you are on international drive you have several options.
They have a bus service where you can get a weekly pass or a book of tickets which works out cheaper and more frequent than some of the shuttle services.
Universal studio's is usually walking distance on international drive, for me about 20-25min walk, found it sometimes quicker than the bus plus the additional walk from the station.
Problem with disney is, they use to do fireworks every night but no longer, when they have the late shows for the fireworks you won't be able to use the public transport due to the hours they finish, in this case hiring a cab or a car is more suitable. Disney itself is a bit off the main stretch so using a cab or dedicated shuttle service is better.
Top and bottom of international drive you have outlets and also another mall near the top, I love fishing and going to sea bass pro in the mall!
With most parks you can buy a week or longer pass for them which I recommend, I was out for two weeks and got pass for two weeks for all the parks, not a bad price either, just don't buy knock off tickets get them either in the hotel or at the park as the tickets work in par with your fingerprint.
Parks are brilliant and plenty of things to do, I went down miami and kennedy, if you do a full day at kenedy space station get a cab to and from if you have no hire car, this is due to the shuttle gets in a bit late and leaves a bit earlier from when it closes, if you do the full package there you will require the full day, I did the full package, dined with the mr astronaught.
There's so much to do, bush gardens, miami, kenedy, universal, the two aqua parks (one by seaworld and wet&wild is on internaional drive and easily walkable), seaworld, etc....
There's a small little park with go karts at the top of international drive close to the outlets as well, okay for cheap fun and arcade, also on the way to universal if you walk up you will see a wind tunnel if you fancy floating around in that giant fan
There's just so much, its better if you go with someone who's been before, helps to break things down and navigate. My mrs has been there more times than hot dinners.
Eating there's plenty of places, I mainly went golden coral and pondarosa. There's bostons red lobster as well on international drive and the list goes on.
