Reporting back:

Ethan is trained up on posters. He caught on quickly, did most of the work for the later posters while I documented. We could both work on being more speedy (which is to say that he was slow but not much slower than I).

We got one post (four posters) in for West Seattle, but during our first poster in White Center we had a sheriff drive up on us. I spotted the car and told Ethan that we should walk away, and the car came down our street and tried to cut us off by an alley. We turned around, waited for the car to try to get ahead of us, and juked the cop pretty easily