Your green card will be processed at your first point of entry into the USA and then sent out to the address you provide them with. So if you arrive in California first, your green card will be processed there. You can apply for your SSN in Oregon when you get there alright.
Thank you guys for your quick reply.
One thing more, can my friend (I gave his mail address) send the green card to me from California to Oregon through DHL or UPS , etc.
Regards