Here is a quick 2 line change to enable ssh for root.

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.orig
sed 's/PermitRootLogin no/PermitRootLogin yes/' /etc/ssh/sshd_config > /etc/ssh/sshd_config

If you want the changes immediately before a reboot also execute:
service sshd restart

Again, very handy in kickstart.