Is there enough room to park an RV at the trailhead?

yes plenty of parking but 3 miles of gravel road

Driving through the forest road patch with RV would be tricky. There were a few turns RV might not be able to make it due to length

Yes, the parking is spacious. I went after 4pm and only few cars were there.

I do not recall the parking spots being deep enough to accommodate an RV, but the few times I’ve been there the parking lot has been only sparsely used and I think you could take up more than one spot.