Good news for you is that the south rwy is closed, so all traffic is using the north rwy (except some smaller Dash TOs on the cross rwy).
Marine Drive is the place from sunrise till 10:30AM and again from around 7:30PM till sundown. In between the top floor of the parking garage is the place to be.
On Marine Drive u can just choose your spot ... there is a spot at the beginning, middle and end of the rwy - u cant miss it. Parking garage also offers partial apron overview and is great for TO
or landing shots pending in which direction they use the rwy.
also has 2-3 fighter movements a day , usually the Pair comes back 90 minutes after TO
. This Thuesday a Globemaster from Mc Chord was doing 7 Touch and Gos .... this seems to be more seldom ...
Have fun, PDX
offers interesting traffic and great spots, which I think overcomes the lack of heavy movements.