If you can manage the time to get a little farther south, try to get at least to Ruby Beach or other coastal areas.

If you are going to the Columbia River Gorge (e.g., for waterfalls and hiking), you can cross over to Washington and hike up Beacon Rock, which is a neat hike and a beautiful view at the top on a relatively clear day.

If you just want to do something in Washington, you could explore downtown Vancouver and the Vancouver waterfront.

Everything else is either, or both, a bit farther away (e.g., the Coast) or closed for the season (e.g., Ape Cave).

Did not notice any do-not-enter signs at the trailhead or the turnoff.

Icy right now in Portland, but temperature is supposed to get into the low 40s today and only go down to a low in the high 30s tonight, with rain from this afternoon through tomorrow. Road conditions will probably be gradually improving throughout the day and rest of the weekend.

You will have time for a brief exploration of Seattle plus one other region of the state. If you have never been to the Pacific Northwest before, I strongly endorse anybodyiwant2be’s suggestion of a counter-clockwise loop around the Olympic Peninsula. If possible, squeeze in visits to Cape Flattery and First Beach too. The peninsula is absolutely beautiful in the misty, rainy fall.