(1) Go to the menu and push Clock. You can choose how it displays (large, small, or analog) when you are in that mode, or under the advanced menu

(2) As accurate as any GPS, with 30 feet or so. Depends on how many satelites you are receiving. Holding down the Map, Menu, and Cancel button for a few seconds brings up a host of options to see, including one that shows how many satelites you are currently receiving, etc.