Completed drilling through a total of 43 ft of RR ties 12 holes at 43" each. This would have been real easy task with a 3/4" drill but I couldn't rent one. Ended up using the 30" auger with a 24" extension. The flex drill bit I got was useless for this.
I also threaded the tie bars today. It was a good excuse for me to purchase a metric tap and die set as well as the 3/4"-10 die required to do the job.
So all that is left is excavation across for the tie bars and installing the last two posts then finishing the driveway. I will probably leave the driveway in ROC for this year and gravel next year.