You're in for some real treats. If you like hills, and who doesn't, head over to Ferndale and climb the backside of "The Wall", aka Wildcat Ridge. Loop back home by heading through Petrolia (small bar and store) and Honeydew (small store). There's a small hill coming out of Honeydew as well. When you want more, head south out of Honeydew over Wilder Ridge, then come back out to Redway and the Avenue of the Giants (flat recovery) via Briceland Thorn Rd. If you are an animal and want still more, head out towards Shelter Cove after doing Wildcat and Wilder Ridge and go south on Chemise Mt./Usal Rd out to Hwy1. (That's 36 miles of unpaved, so don't go too skinny on the tires; you can cut the unpaved down to 24 miles by shortcutting at Thorn Junction away from Shelter Cove (south). From Hwy 1, go east to Leggett and drag yourself on home. If you can do that in one day, you're some kind of rider.
There's also lots of rides to the northeast of you, but I don't know them well. Maybe send a PM to TromboneAl, who lives there, for some advice on those. TromboneAl is almost never seen on the NorCal forum, but is a regular on the oldies (50 plus) forum.
As far as the overall cycling scene in Eureka, I don't know diddly about it. I don't live there, I just ride through regularly on my bike. I never see very many cyclists, but the ones I do see definitely have taken a large dose of HTFU, like the guy coming up The Wall on an old mountain bike with bear trap pedals, no shoes and his fishing gear on his back. I guess you may have to create your own scene.