NodeMCU second HARDWARE serial TX as a debug port
ESP8266 Arduino core has Serial1 as write only hardware Serial on io 2 as TX. IO 2 is D4 on NodeMcu and Wemos D1 mini. 

To use the USB chip of the NodeMcu/Wemos with Serial1 you could wire io 2 (D4) to TX. This would not disturb the flashing mode, because bootloader would still listen on standard Serial pins. I tested it.

And for RS485 adapter swap the Serial to io 13 (D7) as RX and io 15 (D8) as TX with the Serial.swap() command.