Take Davison Road (it was unmarked in late July 2006) to Fern Canyon. The road is unpaved and you’ll have to cross three small streams (our mini van did just fine) and you’ll need to pay a CA state park day use fee. Take Highway 101 north from Orick (2 miles) or south from Crescent City (30 miles).
Your effort will be well worth it.
A local man told me that they filmed part of Jurassic Park there. Not sure if it’s true or not, but is certainly believable.