If you really enjoy fiddling with connection problems and gateways freezing you should try using the gsm gateway. At first it froze up every day or two. I now run a second mcu just to check connectivity to mycontroller and resetting the gateway when it fails. This sometimes happen a couple of times a day.

@Nick-Willis It's simply a case of attaching the serial Tx/Rx on the pi to the Tx/Rx on the arduino (use 3.3V arduino or a level shifter if using 5V pro mini).... Don'e be tempted to use the pi 3.3V supply for the radio or pro mini - take the 5V supply from the pi and use this via a regulator to get cleaner 3.3v...... Originally I used the 662k, but now use AMS1117 3.3V as it is cleaner DC and can give more current for the radio tx pulses.

@nick-willis interesting thanks, adding it to the queue for the next release (https://github.com/mysensors/NodeManager/issues/365)

This is on my todo list. I hope to get to it soon.