You can get by without a GPS. Go to Google.com, click on "more", and downlaod a trial version of Keyhole. After 15 days you have to pay them $29 for a year.
with keyhole, you can locate the coordinates of any point on the earth within a few feet. In some instances it is better than a GPS as you are not hampered by weather or trees.
After you find a picture of the topography of your coordinates, just walk over there and pick up the Cache.