Oh yes, the PNW rainforest changes things.

From the pictures I couldn't get a sense of that density.
I've taken a few hikes in the wet side of Washington and been astonished at the density.

(Posted pictures look about like Colorado which is quite passable under the trees.)

In addition to survival supplies, trade goods might be the thing to have as you'll probably be staying awhile (Unless you decide to buy and bring that jet boat I keep mentioning :-)