This island has been in the news recently; see:
https://www.northcoastjournal.com/NewsBlog/archives/2019/10/12/eureka-schedules-ceremony-for-return-of-duluwat-island-to-the-wiyot-tribe
https://www.latimes.com/california/story/2019-10-22/eureka-wiyot-indian-island
https://apnews.com/ad0b65520930493eb107aac8fb617f10

The official name seems to be "Duluwat" now. Most of it doesn't appear to be part of the national wildlife refuge as currently mapped.

Stagecoach Road at Mill Creek was washed out in 2017. As of June, 2018, the road was still not passable at this point.
All traffic north- and south-bound along Stagecoach Road are forced to turn around at concrete barriers that block passage at Mill Creek.
A jerry-rigged wooden pedestrian bridge has been constructed by locals to enable foot-traffic across Mill Creek.

https://www.openstreetmap.org/way/599015991 - is boundary=national_park really fitting in any way?

unclear if this trail fords the river here or there is a bridge, no bridge is visible on aerial imagery, update needed

Humbolt --> Humboldt