Search the forum on broadcast redirect via SOCAT. That was the trick used by others to get a stable link when the network disconnects. I also prefer that on private WiFi links as a configuration free way to connect from any GCS. The GSC connects to the drone then, not the other way around (no need to use MAVProxy).
I also wrote some scripts here:
For streaming (over WiFi) but you could take the APM start and broadcast scripts. I got the information from here originally:
