I can't speak to NASS, but know for our area (Wisconsin) it seems like in general West Point SLS is looking for scores above 60 in each area, with math being the most important, then CR (I really don't think writing would help or hurt you immensely unless it was way off - like 35 or something).
I haven't seen a geographical breakdown for any of the summer seminars but it seems like the closer you live to the academy whose SS you wish to attend, the more difficult! I'd say that living in Oregon, you have a good chance from a geographical standpoint for any of the academies.
But if you're just looking for something to strive for on your PSAT tomorrow, I'd be shooting for at least 60's on the math and CR - obviously the higher you can get from there the better!