Windwalker,
Welcome to Flyertalk! The Crown Plaza would be the closest of the two. I hear it's nice but nothing special. The Westin would be a little further but definitely not a hike. I love the Westin. It was the flagship of the chain when it was an independent. The Westin HQ was next door. If you need Marriott points, the Madison Renaissance is next door to the Crown Plaza. The W is also not too far away along with Coast's Paramount and Roosevelt hotels. There is also three Kimptons nearby as well. There is quite a collection of great downtown Seattle hotels. Hope this helps.