From the Web User Interface (WUI) you can save the backup of all your configuration files on the disk where you open the WUI. For the restore, you still need to install a new IPFire machine but as soon as you can access the new WUI, you can restore the old configuration file.
For experimentation purpose, I also created a mirror image of the internal HD on an external USB disk, and adapted the image to the different size of the external disk. This way you do not need to reinstall anything, you just need to boot from the mirror disk.