It's the nature of highways to go to and through towns. It's only when traffic becomes too slow and bothersome that the town and highway department make a bypass - hopefully one that speeds up traffic without loosing business.
On the map it looks like US101 goes right through the middle of Tillamook, but it uses 2 one way roads (Main and Pacific). Both are 13 blocks long.
ODOT has started on a project to improve the US101 and OR6 intersection in Tillamook
http://oregonjta.org/region2/?p=tillamook-homeI just make a quick scan of Oregon US101 and did not see any town bypasses. Stick with I5 if you want to bypass towns.