Now I question whether all this extra circuitry is worth it.
The CP2104 will draw 18.5 mA max when powered. So is it worth it to use BUS power mode to eliminate this current.
If you think so then you need to do this with RTS and DTR.
You don't need the transistors anymore.
Notice that it uses a 1G126 not the 125. So you might as well use the 1G126 for TX and RX
You might consider using the quad buffer.
