I think this may be Oregon's state exchange:
https://www.coveroregon.com/Oregon may be different but in Massachusetts the insurance companies participating in the exchange sell the same policies directly from their web sites at the same prices: you only need to go through the exchange to get subsidies (if you meet the income thresholds).
There is more documentation required for going through the exchange to verify your ID for subsidy purposes. This can make the application take longer. This is the list of participating insurers in Oregon
https://www.coveroregon.com/participating-insurance-companies/Like I said you might be able to apply to one directly if you earn more than the thresholds for subsidies. IF you want subsidies you must go through coveroregon.com (which redirects to healthcare.gov)
I wish you the very best of luck. The ACA means you WILL be able to buy insurance and the premiums will be "affordable", but it's still a complex and time consuming process. I expect you'll purchase travel insurance to tide you over the period while you're moving before your US health insurance takes effect ?