IIRC I was to the TH twice last year. Up to where you cross Cunningham Ck at RTC, the road is a rough 2WD gravel road. After that and above the switchback, it's a rougher, steeper 4WD road, I put my Tundra into 4WD LR. When you get to the TH spur, you'll cross Cunningham Creek again, but this time wheels in the water. Last year in late-June 12-18" deep at the crossing, Cunningham was rocking. There's a mine pad to park multiple vehicles right at the TH if you prefer not to cross the creek with a vehicle. I'd have no problem leaving my vehicle for a week.
Enjoy the mosquitoes.