Thanks for the responses!

I'm nervous about the 30 minutes since technically NW can cancel my seat 20 minutes before flight time if I don't present myself at their gate for boarding (and give it away to a standby).

This means even if the QX flight operates right on time, I would have just 10 minutes to make my way from the QX ramp to the NW concourse TSA checkpoint, clear security, and then proceed on to the NW gate -- thus I would have to count on clearing security in 5 minutes or less.

I know of a few "smaller airport" TSA operations which reliably take 5 minutes or less - but I'm not sure GEG falls into that category.

(I was actually hoping to hear that NW had moved into the AS main-line jet concourse, as I found that set of gates to be woefully underutilized on my past trips to GEG.)