We use a cheap Motorola security camera (Focus66). It has sound, movement and adjustable temp notification to a smart phone via the web. It doesn't have a battery backup, but we could always use an inverter circuit. However, if it ever loses power I figure it's time to head home anyway. We connect it with our Verizon Jetpack mobile hotspot, but can also use a campground wi-fi if cell service is nil.
The camera works well in low light and it's easy to check in on our pup through a third party web server. Of course that is also a drawback, as you must depend on that service. It has worked well for us so far even though we only use the free service of notifications and live viewing. There is a paid option for archiving video, helpful for breakins, etc. There is no memory card.
2003 Itasca Sunrise 32v F53