While not part of the I-5 series of caches, this is pretty close to the freeway, so may make a nice side trip. The location also offers hiking and mountain biking.
The coordinates are to the first part. You are looking for set of numbers at these coordinates.
Instructions for the second location are:
Take the numbers you find at the first site, and make them into one 5 digit number (Start from the top). Subtract this number from the following to get the coordinates from the second part.
N 48' 24.068
W 123.06.647 (Subtract number from above to get actual)
To check, the final location is less than a half mile away.
Due to tree cover, the second reading was taken on the road close to the actual location. It is within 30 feet. Two hints: 1 is for the first location, 2 is for the second.
If you get a chance, be sure to ask Sweetie-D why she likes this cache.