We're big on blanket fort days, turning the whole living room into a big blanket fort. There's also the bounce house place by the mall.
I like taking my son to the Auburn Outlet Mall to walk around. We look at the cats at the cat cafe, he climbs on the car ride toys (the ones you put quarters into), they also have a free play area, and a paid play area (Safari). It’s hard that it opens so late in the day. If you need a place that’s open earlier, you could try the Westfield mall in tukwila they open early and also have a play place. But we also like to put on our rain suits and walk at the park with a bucket and my son (1.5 yo) likes to collect leaves, pine cones, rocks. The Puyallup library also has a play area for kids with kitchen stuff and blocks to play with! Anthem coffee shop is right next door!
You can go to indoor play places like Chuck E Cheese, Safari at the outlet collections, walk around any mall, indoor arts and crafts, I like to buy Papa Murpheys mini pizzas where the kids can add the sauce, pepperoni and cheese themselves and I bake it for them.