Hope this helps.
I've been a Magnolia Resident all of my life. As of right now a commute from Magnolia to tukwilla is about 35 minutes in the morning. Central Magnolia to Downtown is only a 4 mile drive...about 15 minutes. Once past Downtown you would be going against rush hour traffice and you would have an easy drive of about 20 minutes after that. That's as of now. A major highway (Alaskan Way Viaduct) thru Downtown is slated to be torn down in the next few years and replaced with a tunnel.... that will create traffic nightmares for quite a while.
Good luck on your move. I'll see you in the Village!
That said, I would guess the commute time to be at least 30 minutes and at times 40 minutes - that is as long as the viaduct is still standing.
Magnolia is a great neighborhood what with the village, views and Discovery Park. The later should make you feel like you brought along a piece of CO. I would also like to throw in the new option for using mass transit. You could take a bus to the light rail downtown station and then hop the train to Tukwila. Depending on where in Tukwila you work, you might be able to walk or take a short bus ride to your final destination. Here's a link for more details http://www.seattle.gov/Transportation/lightrail.htm . Welcome aboard!
Not too bad if you stay off the I-5, although you would be driving a reverse commute.
The most congested part would be going from Magnolia through downtown Seattle since you would be going with traffic. Then once you are almost to Pioneer Square, past downtown you can take the Alaskan Way viaduct to the 99 Hwy, then the 599 Hwy to Tukwila. After getting on the Viaduct you would be going against traffic and it would be fast from there to Tukwila.
Going home to Tukwila would just be the reverse, fast going against traffic until you exit the Viaduct in Belltown, and then you would hit traffic from Belltown to Magnolia.
Once you get on the Viaduct the commute should take about 10 to 15 minuets. Magnolia to the Viaduct could take 20 to 30 minuets with traffic, maybe more.
I personally LOVE driving from the 509 to the Viaduct then on to Magnolia. It's fast, and a beautiful drive overlooking Elliott Bay from the Viaduct, past the Olympic Sculpture Park and then on to Magnolia. On the weekends or non commute times that could take just 20 minutes total.
Too bad our City Goverment wants to tear down the Viaduct and instead build a fewer lane tunnel route to replace it....maybe...I hope not!
Magnolia is one of my favorite communites and very beautiful. I do have to say though, there are beautiful Sound View homes in Three Tree Point and Normandy Park that would have much shorter commutes to Tukwila and for much less money than Magnolia.
Anyway, just a thought!
Hope your re-location to Seattle is an easy one. A great book for moving to Seattle is "Seattle Survival Guide IV". I used an earlier edition when I moved to Seattle and it was very helpful. Let me know if you have any questions, I am happy to help.