I just followed the google maps directions which take you (from anywhere) into Jerseydale and then on forest roads from there. High clearance and 4wd would be great, but dont believe they're necessary. I have a higher clearance RWD van and made it most of the way ok. The last 0.5/0.75 miles to the ingress coordinates the road becomes impassable even with four wheel drive. You might be able to wrangle a four wheeler/ATV down but large vehicles will not make it. Do not suggest trying to access any of the dirt roads leading to the claim in wet weather.
I hiked down to where Ferguson Ridge Rd intersects Sweet Water Creek and gave up trying to go any further. Steep and tall embankments on either side of the creek, if you want to make it to the center of the claim I think you would need to travel in the creek on foot, which is significantly difficult due to the number of fallen trees after the recent wildfire in the area.