GPS device doesn’t have to be very complex. Simple Attiny2313 microcontroller can be used to read data from SR87 GPS module and display it to 2×16 alphanumeric LCD.
As GPS module transmits data through serial interface it occupies only on wire so there is plenty space left for LDC, keyboard and buzzer. Keyboard is used to enter names for marked locations that are stored to EEPROM. Again, great fun project that almost pushes microcontroller to its limits.