Tracks from the official Universal Studios Escape (as it was known back then) Islands of Adventure theme park have been posted to the official Universal Orlando Resort (as it is known today) YouTube channel:
https://youtube.com/@UniversalOrlando
The soundtrack was released for the 1999 opening, I believe, but these tracks are listed as being from a “2000 reissue” version. I may have the original disc somewhere, and I know it had many more tracks than what have been shared so far.
I am just hoping the crazy track from Toon Lagoon makes it. The custom soundtracks were one of the best things about Islands of Adventure. Toon Lagoon especially stood out with its massive multi-track arrangement with speakers all over the land playing parts of the looping soundtrack. (This would be done two years later with the opening of Disney’s California Adventure when it had something similar for the Paradise Pier section of the park.)
Enjoy!