Suzan is former MSFT but her husband still is MSFT - he's a 20-year employee, currently President of the Office Division. Not that they're not very nice people. But I'd guess she's got the joint checkbook to keep her self-funding these campaigns from now until forever.
Cato, excellent point. This will be a critical race to win. There are several good choices on the D side, but for my money Laura Ruderman has the best track record as far as being electable in a district which is not an obvious D demographic. She ran in the long-Republican-held 45th District in WA, and was elected twice, no small feat. She's smart, a savvy campaigner, and was an excellent (and very accessible) legislator. That's my two cents.