Inconsistent Shipping Method Causes Delays

Sometimes my orders come directly from Tualatin OR to Hood River OR in 2 working days.  Sometimes the order goes from Tualatin OR to Seatlle WA to Hood River OR in 5 or 6 working days.  This has happened both ways on battery orders, so does not seem hazardous materials related.  Why is this inconsistent shipping route happening?  What can I do to insure my orders are shipped directly to Hood River (70 miles away) in 2 business days, and not routed to Seattle for delayed transit time?