This map may help you to orient yourself.
http://www.aaccessmaps.com/images/maps/us/fl/o rlando_disneyworld/orlando_disneyworld.gif
The pink area in the middle is univeral studios, near Wet and Wild, just south of that you can see "Sea World".
The thin winding road between them is international drive (not the green straight road which is a motorway).
Now look at the huge pink area in the bottom left, that is the disney complex.
Now when you think that the Universal Studios complex contains two massive theme parks, PLUS about 4 hotels, AND a complex of bars and nighclubs, you can see how big the Disney complex is, and how far apart all the disney parks are.
I have always had a car when I have been in Orlando so never needed to use the public transport, but I think getting from international drive area to the Disney parks may not be that easy.
I believe if you stay at a Disney hotel you get free transport to any of the parks, but of course you have to pay extra to stay at a Disney hotel.
btw, it is possible to have a great holiday in that area without going to ANY Disney park.
The universal parks are great, wet and wild is great, and my favorite park was Sea World.