On the west side of Sandy River Delta Park looks pretty good. You could park on one of the trails that come off of I-84 and it’s a short walk down to the river. You’d have a great view as you smoke, and the roads through the park are pretty well covered so no one should notice a car there. There’s no houses across the river, either, so no worries about someone spotting you from there. Just a short ways down I-84 is a DQ, which would lead to some easy snacking after. Great view, private, and good food nearby, what more could you ask for?