Free: Contests & Raffles.
there should be plenty of birds on the northern edge of the refuge.
There are many doves on the rez. Don't know much about SSide. Hunting the rez will be a shorter drive for you if your coming from Sportsmen's. Check out any cut corn or wheat fields that have orchards or hops near by and you can't go wrong. Standing water in those fields are always a plus as well! Cackle- since when do you not have to have a hunting license to bird hunt on the reservation? I wasn't aware of that.
Never hunted the Sunnyside area for doves but I think you are better off buying a REZ permit and getting a map that shows feel free to hunt land... Then just drive around until you find a good looking field.
I always buy mine at Bi-mart. I don't think the 3-day thing is worth it because it costs $15, might as well pay $35 incase you are ever back this way and want to make a quick upland or waterfowl hunt .