Sims 2 - how can I combine existing Sims games with Origin's Ultimate Collection?

I solved my own problem and thought I'd post it in case anyone else encounters this issue. 

You'll want to Copy + Paste the files from your original game from the EA Games > The Sims 2 > Neighborhoods > N001, N002, N003 etc into the new folder EA Games > The Sims 2 Ultimate Collection > Neighborhoods to replace those neighborhoods. 

I did the same thing. I have a lot of old neighborhood data from previous installations that I wanted to keep using. I had migrated game data before without any problems, as I had changed computers twice since The Sims 2 was originally released. However, I could not successfully transfer the files from my original installations to the Ultimate Collection. You copied the contents of the neighborhood folder from your original Sims 2 folder into the corresponding folder in the Ultimate Collection directly, correct? And this worked without any problems? When I attempted to do the same thing, I got the same result as this:

http://answers.ea.com/t5/The-Sims-2/Sims-2-Ultimate-Collection-won-t-load-my-neigborhood/m-p/3199427#U3199427

The neighborhood I tried to copy into Ultimate Collection was a default neighborhood, so I simply replaced the file. When I ran the game, that exact neighborhood was completely missing.

I was able to copy the folders over without any problems.  Did you make sure to delete or rename the files with the same names in the Sims 2 Ultimate Collection > Neighborhoods folder? 

Same here, I wanted to replace pleasantview from my old sims 2 double deluxe game to ultimate collection and now the neighborhood won't show up in the game