I found a PDF showcasing some of the biggest trees in the olympic national forest a few hours west of Seattle. I visited a few of them recently, and I think you should too. the western side of the olympics is quiet logging country, but the national forest and national park are full of these ancient beautiful trees, hundred year old trees growing out of much older mother logs
the world's largest sitka spruce is estimated to be roughly 1000 years old, the tree stands 191 feet tall, 17.7 feet in diameter, is on private land in Quinalt but there's a public path to see it.
what i believe was once the the world's largest western red cedar is a 20 minute drive north, there's a sign marked "big cedar tree" on the US-101. A storm felled it in 2014, but it's still alive and healing. It's estimated to be 1000 years old, too. the new champion is the Duncan Cedar https://en.wikipedia.org/wiki/Duncan_Cedar which I didn't visit.
pictures don't do them justice, obviously.