How many days? 1.
Based on watching the EB for the past few years I'd say your probabilities stack up as follows (for arrival into Seattle):
50% on time or less than 30 minutes late
30% 1-2 hours late
10% 2-6 hours late
5% 6-18 hours late
5% train cancelled with no alternate transportation.
November doesn't usually have cancellations but early season blizzards and freight derailments can happen. If the train is cancelled you will be notified as soon as Amtrak makes the decision (usually the day before your scheduled departure, though short notice is possible). Note that Amtrak sometimes cancels trains for several consecutive days to allow trains/crews to get back on schedule, so if you want to be 100% comfortable be prepared to book a last-minute flight to PDX should that rare event occur. The latest I've seen a train is 24-25 hours behind, but this happens so rarely that it's not worth planning for. If you give yourself a 12-18 hour buffer by leaving the next day you should be safe.
Mark
Ok folks, I'd like some kind advice. I'm thinking about taking Amtrak on my first cross-country journey to Portland, Oregon. I'm thinking of doing it in November, as i've seen several days via Amsnag where the Roomette ex msp to pdx is showing $187 plus 187 for rail fare... msp-sea on 7 and then cascades 513 can choose business seat for 16 more... getting in on the 7th of nov as an example and leaving on the 5th from msp... now if i am to schedule an outbound international flight from portland, how many days should i plan for if a possible delay were to happen enroute?
I'd like to stay in PDX a few days prior to boarding the plane(s) to jet off to Asia.