I was at Black Rock in my 24 ft Motorhome, and traveling with my co-worker, he was in his Ram 3500 quad/long bed with a 30 ft Avion TT behind it. No real issues up or down to the park, there were several other long rigs there when we were. Yes, in the switch back (there is only one) you have to look ahead as you are in the other side of the road, (and there are a couple of near 90 degree curves) but that is true for virtually anything longer than a car or pickup.
Some of the sites are listed at 40 ft and a few at 50 ft. There is one site that is probably 60 ft or more deep, would be a issue backing into it as it is not angled like some of the others. While I might not recommend it for a 40 ft triple axle fifth wheel, a truck and a 27 ft trailer would not have any issues.
I just finished looking over the park web site and the reservations web site and cannot find anything that specifies a 25 ft max recommended length. I will agree you need to exercise due care and caution and as the web site says, "RVers should be comfortable driving on steep, winding roads.".
Charles
Looking south toward Town of Clayton from Visitor Center
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Sunset view from the deck on the campground loop.
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Both of us. Thats a 35 to 38 ft Class A you can see thru the trees just above the Avion. Its the next site over.
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