"Is there a more straight-forward way to start from a dependency that I need to install and find the RPM on the Fedora disks for an application that will provide the dependency?"
You can search the Fedora install CDs for the rpm package. Install CD 2 has the most rpms so search that one first. You search a CD by mounting it and then using the find command. Suppose that you were looking for gnucash. Then the find command would be:
find /mnt/cdrom -iname "*gnucash*"
Be prepared. Create a LifeBoat CD.