Go to the Tillamook county courthouse and down in the basement is the surveyors office. Ask to look at the tax assessors maps. You will need to know the Township, Range, Section and quarter section of the property you are wondering about. There are some general maps there that you can get started with. A portion of the Wilson and the Trask are in Township 1 South, Range 8 West, and flow through various sections. Upon finding the property you want to know about write down the tax lot number and the map number ie tax lot 700, map 1S 8 12AC is a lot in the Narrows on the Wilson River,
After you get the tax lot numbers, go upstairs to the clerks office, main floor, North end of the building and ask one of the clerks for the ownership information on that lot. You should get a copy of the assessed value, taxes etc but it will also have the owners name and address. Phone numbers are not provided so your next step is a phone book and a lot of quarters.
Good Luck.