I navigate by compass and dead reckoning. I am sorry that I can't get you what you need. The route will bear southeast along HWY 8 and Old Harrison Ferry Mtn. roads until turning north on Rocky River Road crossing HWY 30 to Goodbar and Turkeyscratch Mtn into Campaign and a turn to the southwest on the old Sparta road back to McMinnville. Let me know if you plan to make the ride. The route up Old Harrison Ferry is the best climb to Plateau I know.
I'd come, but I checked and it's a 3 hour round trip drive for me. That, plus 3-4 hours of riding is longer than my dog can cross her legs. If Lisa and the girls were home to take care of her, I'd join you. Hopefully you'll do it again another time. It sounds great.