The short answer is: Yes, there is such a beast. Several, in fact. But you can聮t necessarily expect a GPS unit like you see in some cars that says, 聯Turn here, meathead.” That聮s because not everything is digitally converted to detailed maps useful for hiking, for one thing. And only higher-end GPS devices have the memory capacity to handle lots of on-the-ground detail.
Garmin Geko 301

That said, you might take a look at the ($500; www.garmin.com). This is an exceptionally powerful unit, with a bright color display, excellent satellite-acquisition technology so you pick fixes accurately and quickly, and expandable memory using microSD cards. The GPSMap 60CSx comes with a national road database, useful for driving (car kit is $210), and can take a number of products from MapSource, such as National Parks, West ($110), which has detailed maps of every national park in and west of Colorado.
The 60CSx can also handle bicycling duties, and you can purchase a handlebar mount for $18.
But, don聮t expect to be able to stop anywhere, hop out of the car, vanish into the brush, and call up a detailed map. In many places, you聮ll be able to find your rough location relative to key landmarks, but not much in the way of topographical detail or even some obscure logging/jeep tracks. But then, at those times you simply input a waypoint, and use that to mark your track back.
And because all GPS units handle waypoints, you can get by with a less-expensive one if you wish. The Garmin Geko 301 ($230), for instance, stores 500 waypoints, calculates altitude, has a compass, and is waterproof. No excuse to get lost with this unit. Or, the ($200 with outdoor kit; www.magellangps.com) has a pretty good all-U.S. topo map, an armored case, and more. It聮s a solid, basic unit for keeping on track.
Happy trails to you聟
Get more advice from the Gear Guy as he picks this season聮s top gifts in You聮ll probably find a few things to put on your own wish list, too.