Paul MN, I'd like to add wireless doorbell options for tenants + cameras for security in front/back/garage area. 

Wifi, security system codes, video doorbells, smart locks, cameras, speakers, self installed devices in their room etc.I'm sure there are landlords that have some of these in their apartment rentals too

If you are also going to be away, GET A SECURITY CAMERA.

A door area camera might be nice in a sketchy area, but Texas requires door viewers which work well with dusk to dawn led lamps...and a decorative metal security screen type door is probably better security than a camera.

Then set up the lights, cameras and communicate with the police.

I had our maintenance company run a camera down the pipe and it had not broken, at a cost of 150 dollars.Cut to last month, I went to the house because she was moving out and I wanted to put stakes in the ground to keep it from happening again.

Since then a few suspicious things have gone on around the house, nothing major but enough for me to install surveillance cameras.

You may want to leave some privacy to your tenants - that builds more trust than cameras and spy software.

Use a rooter router camera through the inspection hole see if the pipe is even there.

Alarm.com is a new player to the market who has a excellent cloud based system which has a lot of bang for the buck, can intergrate camera systems, energy management, and security all under one platform and easy to manage from anywhere in the world being cloud based.