Jason
Here is the tracks for Nanango to Kingaroy north and south about. The south about route I found easier however stopping over in Nanango is a good restocking point. http://www.gpsies.com/map.do?fileId=eqocwgchmnufhyri
If you look at other rides I have done you will see some from Yarraman to Nanango. The best route I can suggest for you is to go from Blackbutt to Yarraman via the rail trail (there are other offroad routes but longer) then leave the railtrail just before Yarraman and go via Old Coach Rd to Nanango. The Old Coach Rd runs pretty much beside Yarraman Creek heading due north. Then the routes from Nanango to Kingroy above.
Eric

Here’s the link to the Garmin Track Log: https://connect.garmin.com/activity/1008356526
Here’s a link to a google map of the route: https://www.google.com/maps/d/edit?mid=z0_cdVp26EjQ.k-PZARQStHds&usp=sharing
Here’s a link to the GPX: https://sites.google.com/site/ennisfiles/home/KingaroyToYarraman.gpx?attredirects=0&d=1

We did it the opposite direction to how you wanted to do it.

We’re riding through this area as a multi-day ride on the Labor Day weekend. Do you want to join us?

Neil