The distance from Blaine to Portland is 284 miles/457 kms. Can this distance be ridden in 2 1/2 hours? To accomplish this one would have to ride 183 kph average. It is not possible to ride this distance down the Interstate 5 during daylight hours at this speed. There is too much traffic and too much enforcement.
To attempt this calls for some planning, imo. One would have to leave Blaine at approx 1:30-2:00 a.m. best on a Sun.
At that speed one's bike would drink a lot of fuel and one would need to stop at least twice. This calls for leaving the freeway and many stations are closed at that hour.
It might be best to take 405 to go around Seattle and avoid all those over and underpasses.
This is also a truck route and there is often tire debris on the road. It would be dark and difficult to see hazards.
The road doesn't really open up till South of Olympia.
There is a lot of enforcement on the Interstate and also night trucking. With cell phones it's most likely that someone would call a rider travelling at that speed in to highway patrol.
I've been driving that road since '74 and riding it for the last 10 years. Often enough, day and night to know there is enforcement.
I posed this question to several riding friends who live in Seattle. Can a one ride from Blaine to Portland in 2 1/2 hours. No, it's can't be done.