If you're looking for something easy, with little to no wire run, a wireless IP camera will do the job.  

Also, you can get a wireless motion sensor security cam/monitor with phone app. and that you can actually talk into it.  

There are wireless ones that are out there but we do not want to be solely dependent on our internet working for our guests to be able to get in.

Get the ring doorbell camera  it can be installed wireless and connected tO your WiFi. 

Since wireless internet hotspots are just about everywhere these days, some agents meet their clients at local shops such as Starbucks or Panera Bread (Click here to see a list of hotspots in Texas).

There will be wireless options.

Make sure if you are using a wireless network that it is private and encrypted properly and nobody else is using your computer.

I also report the call as spam so the wireless carrier can take action.http://www.businessinsider.com/spam-phone-calls-caller-id-spoofing-area-code-2017-9

Security System:SimplySafe provides a pretty good system that works off wireless, so you can use it at a property and then take it with you when you leave since there is no hard-wiring required.

The lot we personally own and operate are pay by space lots with a solar powered wireless kisosk.