Here is my corrected copy of IP, which should work for others. I tested it. Here's all you need to do.
Make a new folder in your Sims 3 Saves folder called IPonlyRdy.sims3 and copy these four files into it: https://www.mediafire.com/folder/hh78ai99s6a1y/IPonlyRdy
When you next load up your game, it should be your first option there with other saved games.
I tried to only do the bare minimum changes, but I wanted to avoid lag in your game; so you do get some of my redone EA homes. I did redo them so they only need IP - no other EPs or SPs or any store stuff.
I had redone most of the lots using all the EPs and SPs and some store stuff earlier. If interested in any of those lots, look in this folder and you can do individual replacements:
https://www.mediafire.com/folder/o3g07w12a9d20/Lots
If you have all the EPs and SPs and own the store (or lots of it), you could download these files instead:
https://www.mediafire.com/folder/xp7wkoer3drf0/IPrdy
(Your new folder would be named IPrdy.sims 3 and would go in the Sims 3 Saves folder. I made many more adjustments to this version as I was simply making it for myself.)
You could, of course, have both saves and see which you like better.
IPrdy simply means Island Paradiso Ready to Play in my shorthand.
IPonlyRdy means I made it with only the IP expansion pack.
I hope you will find these versions much more playable.
NOTE: I make changes to four ports as they were problem ports. They are tagged NO visitors allowed to avoid Sims wondering around there on their own. IF you play your sim(s) there, they won't get any visitors unless you change that designation using the cheat enablelotlocking.