I think this is really neat. Been wanting to create an ESP32-based environment monitoring system for outside to replace the cheap 915 MHz weather station I have. CAN might not be a bad technology to do this with since I don't really want to have yet more things emitting around 2.4/5 GHz
This solution uses 2pair standard rj11 telephone cable(tested upto 15meters - can be longer) - one pair is for CAN-L/CAN-H and 2nd pair is for dc supply between 6v to 24v, esp32 firmware offers failsafe A/B upgrade mechanism over CAN.