What are your security concerns? Break-ins? Vandalism? Storm damage? What do you want to be able to see?
While waiting for your reply, I’ll mention that we have been happy with SimpliSafe. I’ve had it in several homes. It’s inexpensive, flexible, and easy to set up, scale, and use. You can add and remove devices, including cameras, door/window sensors, and motion, smoke, freeze, water, and glass break detectors.
Monitoring is relatively inexpensive and can be suspended if, for instance, you’ll be living in the house for several weeks. You can also use it without central-office monitoring, and just use the in-house alarms, so there’s no monthly expense. I originally bought it for my wife’s peace of mind while I was traveling, so we’ve used the central monitoring only when we’ve been away for extended periods of time.
It requires no wiring, and is therefore portable. Once you’ve sold the house, you can take all the components and install them in your house, or a vacation home, whatever.
@ZonexandScout is right about cameras having to be outside, not looking through windows. SimpliSafe’s cameras use IR for detecting motion, so they won’t trigger when looking through glass.
The system uses an internal cellular module to connect to the central office, so a land line connection is not required.
I will mention that we’ve owned and used SimpliSafe for more than ten years in four houses, and in that time we’ve been lucky: we’ve never had an event that required it: no break-ins, fires, etc.