May should be great, but watch the weather this year. We left the area just before Thanksgiving. Got a lot of rain during the three weeks we were there. 299 was shortly closed due to snow the day after we used it. I consider there to be two major areas of trees. For those north of Crescent City, we used Shoreline RV in CC. Awesome recently renovated FHU park on the bay. For the groves south of Eureka, I concur that Ancient Redwoods is the best. Be advised it closes seasonally & will stay closed until heavy rains are past. May shouldn't be a problem. Call ahead. If it is, Riverwalk in Fortuna is next best. As suggested, use the various RV park review sites. rvparkreview is very good, but I also use Campendium, rvparky, TripAdvisor & Yelp. Different demographics.
