Yeah, back up your entire /home folder.
After you install Fedora, copy the /home folder back.
That's the simple answer.
Here are some complexities:
You may want to create a /home partition (not just a folder, but an entirely separate disk partition), so that you can retain your settings easily when you reinstall Linux. For more info about separate /home partitions, check out this thread:
You may not want to copy back the entire /home partition, as there may be some conflicts in terms of how things are stored in Fedora and Red Hat. I usually just make backups of my .mozilla and .thunderbird folders and reconfigure all the themes and backgrounds and such by hand.