Reddit reviews City Walks: Seattle 50 Adventures on Foot

Look at these cards. They can take one or two per day and explore different neighborhoods

I picked up this

It's great! Every walk has 5-10 landmarks/points of interest to check out (art, restaurants, museums, etc.) A lot of the routes are close to each other so you can stack them. Last week myself and another redditor trecked from the U-District to the Fremont troll and back. A good way to spend a Saturday.

EDIT: Just noticed in your post your concerns about public transit. Each route has a connecting bus route listed from downtown.