In October I seriously doubt you'll have a problem. My DW makes the Bend Trip almost every month From the Portland area ( in a Car however) and seems to prefer the Salem/Bend crossing. A look at the weather a day or two before will make your decision ALL the major routes are very MH friendly. Where in Portland you are going will make a difference 26 the east/north end and 20/22 the south/west end, all things equal. If Ice is possible the advice already given to travel between 10 and 4 is good! Have a safe enjoyable trip!
