Arduino as ISP with serial monitor for ATmega328
Just burn the arduino bootloader to your tqfp. Then connect the tx and rx on the tqfp to the tx and rx on your arduino, and pull the reset line on the arduino low. 

Downside is you have to do a manual reset on the tqfp before programming. If you have an Uno you could remove the atmega from the socket, and connect the reset on the uno to the reset on the tqfp. 

Another option is to connect the TX on the tqfp to the TX pin on the Arduino using a resistor. But for this to work you have to modify the ArduinoISP sketch to make it release TX pin (UCSRnB &amp;= ~_BV(UCSRnB);) and set it to input. And reverse it when data is received on the RX. Not trivial, and only works one way (tqfp to PC).