I had an idea for this type of cache and even a general theme, but struggled finding the proper sound effects. So after some internet searching and head scratching, my girlfriend mentioned a super funny scene on her favorite show, The Office. The scene is from Season 6, Episode 24, "the Cover-Up." Look it up sometime if you're not familiar. Anyways, on with the show...
Stage 1: Arrive at cooridnates with an FM radio. Tune to 100.9 and wait for the sound clip. It will be on repeat and it's only a minute or two long. This should be pretty straight forward, but use the hint if you need it. You will need to decode 8 numbers total, the final 4 numbers for each part of the coordinates. 47.18xxxx, -122.30xxxx (The final is NOT located on fair property)
Stage 2: This is only a couple of minutes away. Park where you can. Enter the trail near the bridge (due west of the final) and look for a small spur trail not long after you enter, to the left. There will be a small creek you will either need to walk across or jump over. Wind yourself back to the final. Use the hint.
You can validate your puzzle solution with certitude.