I'd use craigslist over the local paper. The paper just has apartments in large buildings. A more common scenario in Seattle is finding roommates and renting a house.

"When I emmigrated to the USA, I wanted to live in San Francisco or Seattle - after discovering how much it would cost to rent a rabbit-hutch in Bellevue, we settled in beautiful Portland - the City of Roses - My Mother-in-law lives in Kent and commutes to Issaquah every day - no thanks"

I drove through Portland in off rush hour traffic and how people do that is beyond me. It cleared up, literally, right when I crossed the border. I'll take Seattle with Washington's no income tax policy any day. In terms of what your mother in law does, that's her own choice. There are plenty of ways to live in this city without going through that foolishness. If she can afford Kent, she can afford something in Issaquah.