Believe it or not, I used the technique described to communicate over 340' of Belden 24GA unshielded 4 conductor cable (power, ground, transmit, receive).
I was running 9600 baud and I had to reduce the pull-up resistors (1.5K ohms on each board), but it worked. No signal boosting - nothing but two 18F2221's on one end and an 18F8723 on the other.