If this Arduino - CMMR-6P-60 combination is to have useful interaction with the world, it will need a display. To keep the microprocessor unburdened, it would be best to unload driving the display to another microprocessor and communicate with it using TTL (0-5Vdc) serial.
The Modern Device Serial LCD Board fits our specifications pretty well. Connection to the board is +5Vdc, Ground, and whichever pin on our Arduino we use for TXData (hardware Pin 1 - SoftSerial any free pin). The Serial LCD Board interfaces to any HD44780-compatible LCD display and can use either a 16x1 or 8x2 header. You may purchase the board as a kit or assembled.
Serial commands are sent to the board for geometry setup, special characters, clearing the screen and positioning character writes. The command set is simple to use. Setup commands and special character definitions should be followed by a 300ms delay.
And here's a 16 character, 2 line LCD display for our project. These can be found surplus and as long as they're HD44780-compatible, they should work. The Serial LCD Board will run up to a 20x4 display.