Don't forget that geocaches are not allowed in the Superstition Wilderness Area (or any Wilderness Area, for that matter.)  If you plan to "drop" a cache while you're out hiking and looking for others, you should keep that in mind.  There are a number of caches in the area between Lost Dutchman Park and the Wilderness Boundary though.  To avoid the fee for the privelege of 'parking' at Lost Dutchman Park, I'd recommend one of the trailhead parking areas along First Water Road.


I'm surprised no one has mentioned South Mountain as a hiking/caching location within 20 minutes of Phoenix.  South Mountain Park is the largest municipal park in the country (if not the world) and (at least the last time I was there) there is no use fee.  There are miles and miles of trails and possible elevation changes of over 1000 feet.  It's in the heart of the city and sees heavy traffic but as you get further into the interior you will forget you are in the city. There are a couple of bookmark lists detailing South Mountain caches which would indicate that there are between 50 and 80 active caches in the area.  A carefully planned hiking/caching trip could give easily give even a moderately experienced hiker a dozen cache finds in a day of hiking. My biggest complaint with the park is the fact that it closes at night and you have to wait for the gates to open in the morning to access the main trailheads but, if you know where to go, you can avoid that inconvenience.

Regards,
-- Sprocket