What Peale said, not all caches are long hikes.  Each cache has a rating for difficulty and terrain.  Keep yourself within 1 to 1.5 stars for terrain and you should be fine with kids.
Peale, nice.  I had a Handspring in 2000 I think.  Until it started eating batteries and handspring wouldn't do anything about it.  I drop my gps all the time so I don;t think I could use a handspring 

  I currently have a Garmin eTrex.  Simple but works.  I use to have a Garmin GPS III+ until the antenna broke.   I need to get one with mapping again.  My original use for the GPS is to guide myself back home after a motorcycle ride.  Maps come in handy for that.  Might look into get the GPS V then as I still have my motorcycle mount and power cable from the GPS III.