My particular scenario is that I usually try to run the previous FC and the new FC in parallel.
Be careful, SELinux is incompatible poison from release to release. In theory, it may be impossible to mount a filesystem read-write across differing releases without causing disaster. Turn off SELinux completely, or do the cross-mounts read-only, or be prepared to suffer. Learn about /.autorelabel plus booting with "enforcing=0 single", and be prepared to wait half an hour every time you boot a different system.