A few years back, there was a multi cache here at this rest stop that was similar to this one. I enjoyed doing it, so I thought I'd bring it back. Thanks to TravisL for doing the first one, and giving me the idea and opportunity for this one.
---------------------------------------------------------------------------------
If you're traveling up I-5, this cache can be done and you'll be on your way again in 20 minutes or less, including a bathroom break. You'll end up back on northbound I-5 at 320th. If you're heading east on SR-18, you'll have a five minute detour.
Muggles. They take your cache, intrude on your searching, call in the bomb squad, and generally make a cacher's life miserable.
But what if there were no muggles? Regular caches would be visible from the parking lot. Creative urban micros would have no reason to exist. And what would be the fun in that? You'd might as well move to Nashville.
This cache starts at the listed coordinates, at the northbound I-5 rest area. The final cache location is a 5 minute drive from here (depending on time of day and traffic), and a short stroll. It's a quickie!
For this cache, you'll need to enlist the help of a muggle (or bring an appropriate teammate). Why?
Waypoint 1: Go into the men's room. Get the serial number off of the left side hand dryer.
Call it ABCD-EFGHI.
OR
Waypoint 2: Go into the women's room. Get the serial number off of the right hand dryer.
Call it JKLM-NOPQR.
You can't do both, so you'll need to ask a muggle of the opposite gender to help get the other set of numbers for you. They don't bite. Most of the time.
Feel free to give them a hug if you want for helping you. 
Cache location: The cache is at N 47 18.D(B+H)(I+B), W 122 17.(N+P)P(J+K).
Only 1 car parking space available near cache (Do not park on road!), but more spaces available a few hundred feet away or so. Room for log only, so BYOP. Please re-hide as well or better when finished.
FTF gets $1!
-------------------------------------------
Congrats to kennelbarb & mumadayo for FTF!