I use AC Toolkit pretty often so I think I can help!
1. Install Savegame Extractor and Savegame Installer.
Savegame Manager will only work if you have a cIOS installed.
2. Run Savegame Extractor and follow the onscreen instructions.
3. Remove the SD Card from your Wii when extraction is complete, and insert it to your computer.
The ACCF Gamesave should be in a directory like this....
Computer/RemovableDisk/wiisaves/RUUE
4. Copy the RUUE folder somewhere to your computer, for easy access copy it to the same folder AC Toolkit is located in.
5. MAKE A BACKUP OF THE RUUE FOLDER!
Rename it Original Town or Town Backup for easy identification.
6. Run AC Toolkit, open the RVFOREST data located in the RUUE folder.
7. Edit your town and save the RV Forest data.
8. Copy the RVFOREST data of your new town and paste it to the RUUE folder on your SD card.
(computer/removabledisk/wiisaves/RUUE)
If it ask if you want to replace the old RVFOREST data click YES.
9. Move the SD card back to your Wii.
10. Delete your old ACCF savegame data from the Wii.
11. Run Savegame Installer and follow the onscreen instructions
12. Boot ACCF and enjoy your new town! ^_^
This process can be used to restore your original town data too, in case you mess up your town or something.
I hope this help you with your AC Toolkit problems! :D