External Rx Tx status LED's

What would be a good approach to connect two external LEDs displaying the Rx and Tx (on MEGA2560) activity? I would like to set this up so I can view the Tx and Rx activity, because the 2560 is mounted inside an enclosure.

What Pins would I want to hook these external LEDs up to? :astonished:

See:
HERE
Carefully solder wires to the same pads the two on board led cathodes are soldered.
Run the wires to the external cathodes (leds)
External anodes to separate 1K resistors then to +5V