Not sure on the rating, but I wouldn't take a near stock Gen2 on that trail. Full skids would be necessary on an unlifted Gen2. Most of it is easy, but the rock garden and LONG hill climb could give you trouble and a lot of banging of drivetrain on rocks.
If you scraped the drivetrain on Broken Arrow, Sunflower Mine could beat it up.
Defibvt took his lifted, fully skidded, aggressive tired Gen2 on Sunflower and ended up being towed (by my Gen1
) for 30 min out of the tough stuff. He could give you some insight as well.
It is a sweet trail and beautiful scenery though, hope you are able to make it as a rider if you don't drive it.