@Riverstar 

Good day.

Thank you for your patience.

Do you want to work like this: take power-line units  TL-WPA4220kit for example

Router) ) Wi-Fi ( ( RE305---cable---power-line adapter~~home wire~~~power-line extender(extender the signal to the Wi-Fi dead zone )?

It is ok.

And the following setup is even better:

Router---cable--- power-line adapter~~home wire~~~power-line extender) ) Wi-Fi ( ( RE305;

Note: please make sure the whole house is under the same electric circuit.

Thank you.