Be sure to take the Crack in the Ground road off of route 31. Google might send you to Northstar Road which is like riding a kid's roller coaster.
You'll still experience 7-8 miles of washboard road and a few muddy potholes but there isn't any deep sand or gravel so 4WD isnt required but you do want good clearance. Be sure to go the bathroom before because the road may shake the pee out of you. And as of 6/23, the restroom at the trail head is under repair.
As others have said, it was definitely worth the trip. There wasn't anyone else there today so it was really fun. I got through the first section and yes there were rocks to scramble up and down on but this old geezer made it. Look forward to going back to do more. Also, it's not so remote and I had cell service until the deeper sections. I hope you enjoy as much as I did.