The Hardin Flat road is not too bad. It can be steep in some sections and narrow for two vehicles passing but we were able to get our 43' fifth wheel there just fine. If you are taking Highway 120 the Priest Grade is scarier in my opinion. It is very steep with switchbacks. Check your brakes before taking the route down and plan to use all the pull-outs on the way up. There is also an old Priest Grade road as well. Don't turn to take that with an RV even if your GPS suggests it. That road won't accomodate RV's or trailers because of the sharp turns. Also, don't expect any cell service at the campground. You can pay for Internet but there is no cell reception for any carrier.

Thank you! After reading this I think the comments I heard must have been about the Priest Grade on 120.

Compared to a lot of the other roads at other thousand trails, I didn’t think the red was that bad. It’s a very short drive also. The road to the park is paved, it’s just inside the park where the road is unpaved. I wouldn’t worry about it too much

The main road in (by the gas station) is very steep. If I recall 5 mph is the limit and a good idea. The other road in is windy and thin if I recall. I only drove that one in my towed not the mh.

Road is good. One tight spot in groveland

We had no issues with the road in... 33ft airstream