If they don’t have Wi-Fi, 4G is going to really be your only choice, streaming audio should be OK as it wont require that much bandwidth to stream up (most likely only 256kbps), losing connection would be the biggest issue.
Just hope the cell tower is close and you have people on standby in both locations to re-stablish connection if necessary.
If the 4G signal is ropey try 3G instead there should still be plenty of bandwidth and less people seem to use it if 4g is available.
I streamed with 4G through the Traktor Pro 2, a friend of mine set up a server which I streamed to. You could simply connect to it with VLC. It worked like a charm.