@rogers1313 interesting question, and I’ve been mulling over possible solutions as it seems very attractive.
The area undefined , is power, cost of the cellular gateway, and reliability of the connection.
Its possible to do the individual elements easily – 900Mhz point to point – and cellular – but then introduce a packet with the “readings in JSON”, that has to be pushed between the two, and also manage the resultant handshake ACK to ensure reliability of delivery.
One way to think of it might be with LoRa 900Mhz to a LoRa Gateway on Cellular. The power usage for a cellular gateway may become an issue if its solar powered. With the physical layer and the output on a say ThingsSpeak LoRa WAN, now the readings needs to be pushed to a server. MonitorMyWatershed doesn’t easily support that interface, but there are other servers that might be turnkey, and there is then the need to configure the server interface. Be interested to see if other people have ideas 🙂