Am grateful for these suggestions, otherwise non-Seattlers waste precious time ...wandering and exploring under time constraints.

We will have to try the Centennial Trail ..unloaded with gear. I did find the map ...

and Interurban Trail will use part of it to get into towards Bothell.
We're staying at a hotel in downtown Seattle, not far from REI. I have happy memories of spending over $300.00 US on one of our trips.

As a comment, we did do a separate, "scenic" trip from Port Angeles to Sequim (last year or 2 yrs. ago..I'm losing my head here) on that newly paved trail through the woods (sorry I need a map to refresh my memory)..which strangely we found the pavement too sluggish for faster bike tire movement. Using the old highway parallel returning to Port Angeles was a dream-relief. Better views too!

If a trail is paved, the quality of asphalt makes a noticeable diff. when one is cycling with loaded panniers on long distance.