Rob said: OK, I guess it wasn't as hard as I thought. I don't know who gets the prize. I'll let you guys flip for it.
Not me! 
I was poring over the maps looking for something over in Big Bottom near Rho Creek.
kirk said
Not me!
OK, I won't spill the beans yet, then. But, there is a clue in something you said.
And, you are too far North.
Gee willikers, I'm confused! 
I thought when you said, "OK, I guess it wasn't as hard as I thought. I don't know who gets the prize. I'll let you guys flip for it.", that you meant your location was at Oh Boy Forest Camp. Doug seems to know where you are, and Donovan guessed Oh Boy. I only used "oh boy" as an interjection because it was the only camp name I could come up with. I thought you were over in Big Bottom somewhere.
When you said, "Kirk, to answer your question, the water feature is "big" – but maybe not in the way you are thinking.", that made me think you were by a river (big because it's long) or near Big Bottom (because it has big in its name).
So if your location is Oh Boy Forest Camp, I think Donovan won this round. If not, I'll have to talk to myself and figure out what clue I gave myself. 
I will defer to Donovan because he knew where you were.
So the correct answers to your posting of the photo are: Collawash River, Elk Lake Trail and Road 6380? 
How much trail is left there? Did you follow it very far?