I'm sending out an inquiry to see if there are any garden railroad clubs in NE Oregon/SE Washington specifically Pendelton/Hermiston, OR and Tri Cities (Pasco/Richland/Kennewick), WA areas. My internet searches have come up empty. Thanks for any help!
If your train is up and running. Plan an open house and advertise it here and other places. People who come might be interested in forming a local group. At least you will know the extent of local interest.
If you get minimal attendance, you will have your answer.