I can't really help you with the NE part (my commute is Tigard <-> Marquam Hill) but I can tell you that in my opinion it's better to take Barbur than Sylvan. If you want to avoid the climb up to Capital Hill (which is quite steep but I kinda like it), there's another route you could take:
((Not sure how familiar you are with the area, so you might want to look this up on Google Maps))
Going South on Barbur you can take Multnomah, then take a Left on 71st (a few blocks before Olsen Rd). 71st turns into Alden which takes you to 80th. Take a Left on 80th (which has a bike lane), take a Right on Taylors Ferry (first stop sign). The next stop sign is Washington St - take a Left and that will take you to Hall Blvd, where you make a Right and go to Wash Sq
Hope this helps. Let me know if my directions aren't very clear.