Semtech have a ping-pong demo here but there would be a good deal of work to get that running on new hardware. In any event, simple examples will leave their radio receiver always on and so will draw much power.
AFAIK almost all software work for LoRa hardware supports LoRaWan. The path of least resistance is probably to get a LoRaWan gateway and get a LoRaWAN implementation working, and understand it, before attempting a point-to-point implementation. In most cases it will be easier to get two nodes to communicate via an application running beyond the LoRaWAN gateway.
AVOID USING “SINGLE-CHANNEL GATEWAYS” which are not compatible with LoRaWAN and won’t work with LoRaWAN gateways like The Things Network.