I have a Blink home security camera. Runs for at least a year on two Energizer AA Lithium batteries. As long as it is in range of its base pod, it will wirelessly send video clips to the cloud for storage, alert your phone when it senses motion, and provides real time video on demand with two way audio. Under $100 and no monthly fees.
With the steel case on the trail cam and padlocking it we don't think the adjacent will be able to run off with the cam unless he tears down our yard gate and fencing which will definitely earn him some jail time. Will be using signage that states surveillance is in progress, as the state statute requires it if the camera is not clearly visible as such.