Is your only use for the bike the Portland Short Track series or do you want to actually go mountain biking? For that series, which is the polar opposite of technical (read: barely more technical than a cross course) a light, rigid mountain bike, 26er or 29er, setup 1x9 with light tires would be perfect. Stock wheels are generally heavy, so it might be worth it to get a lighter set if you can afford it, especially on a 29er. You could start with the nicest hardtail you can afford and sell the suspension fork for a carbon rigid.
For riding actual trails in the region which I highly recommend, like Brown's, Hood River area, Mt. St. helens, etc, as a new mountain biker, you'll probably want at least front suspension and a double crank for cross country riding. Use some light racy tires for the short track series and more durable treads for other riding. Again I'd probably just get the nicest hardtail you can afford in 26 or 29 flavor. I prefer the latter, but again it really doesn't matter that much. You won't know your preferences until you've ridden for a season or two, and then you can decide whether to get another bike.