When we crossed 108 some years ago, there must have been a rally of some sort in Reno. We saw clusters of motorcycles through out the area (Tonohpa, Lake Tahoe, etc). But I don't recall any annoyances on 108 or 4. I was in an small SUV trying to see as much of the mountains as possible while traveling generally north from Big Pine to Graeagle (in 2 days).
And the only problem with RVs was meeting a class C on a narrow blind corner on CA4. The grades aren't as steep as on 108, but the area around the summit narrows down to 1 1/2 lanes.
