Hello! This ask has been here for a really long time (I’m sorry!), and you most likely figured it out by now. But just in case, you only need to save the Documents/EA Games/The Sims 2 folder to backup the neighborhood (or Documents/EA Games/The Sims 2 Ultimate Collection, in my case). The Program Files folder shouldn’t ever really be touched and contains the core game files. All your user files/neighborhood-specific files will be in the Documents folder. 🙂
Feel free to send another message if you have any other questions!