I completed Imogene in July. It was my first time off-roading and off-roading the Raptor. I felt it was fairly straight forward and many on the mountain were always willing to help or give advice. I will say, my nerves were high the entire time, and my heart rate never dropped below 100, but it was a blast! Looking back, I would probably only take the trail from Ouray to Telluride based on ascent and decent grades. Passing wasn't horrible, but usually meant you were always spotting for oncoming traffic and finding turns with plenty of run-off. There are a few straights that allow two vehicles, but this means running up a bit of the cliff if it isn't too steep in the area.
Based on another person I know that just went, he said Imogene was close due to washout. So check that link that SimpleJack shared.