It being Monday, the ranger station in Sisters was open. I drove in to get some information. They gave me a fine, big, map of the local National Forest roads with dispersed camping areas marked. It was interesting to learn that what Google Maps showed as a continuous swath of National Forest actually has a bunch of patches that aren't. And I happened to have spent the previous night a few hundred yards into private land.
So I found a new, even better place. Larger clearing, more sun, closer to town.