Last year my framers were robbed at gun point while outside eating lunch, neighbor had a ring doorbell and cameras, but really couldn't make the guy out. 

With camera system you have a few things to consider. 

Add outdoor lighting and some obvious cameras along with some inconspicuous ones.

@Derek Hobart use a 1) channel manager for guest messaging (Your Porter, IGMS, Smartbnb, OwnerRez to name a few), 2) dynamic pricing tool (Pricelabs or Beyond Pricing), 3) digital guest guide where you can embed short instructional videos (Hostfully), 4) WiFi lock (Schlage Smart Connect w/Smart Things Hun or Schlage Encode no hub needed), camera (Ring Cam) and thermostat (Honeywell).

I do wonder if better camera systems would be cheaper, but maybe not.

Equipment: sheets of plywood for all downstairs openings, tools, empty boxes for their stuff, lock sets for every door, stack of 2X4's, long screws, nails, fake security cameras, no trespassing signs with California Penal Code 602 PC, gloves, masks, trash bags...If they won't leave, call the police (who won't help you but them showing up may make squatters run).  

Use your camera phone to subtly video EVERY encounter with her and her parents, to protect yourself from future claims & lawsuits.

Will definitely research the camera option..at the moment there is no internet service..and since we got stuck at the electrical roughing no electricity either so some logistic hiccups but probably could figure something in this direction.The PM and GC are somewhat closer then would be desirable but I don't feel that this is the issue...I am grateful the PM did bring this guy since the 9 I found by various means all didn't work out...this are busy time and so I is hard to find good contractors...I think he is just busy with other jobs and since he figured we missed our deadline (it is student housing) then he just work on my project on his off days from his other promised deadlines...I am an architect myself and paid very close attention to prevent change orders...contract some is agreed and so far he received about 40%. 

I have Digital Watch Dog camera system which I love.

If you decide to go into the Pizza biz make sure you buy a good $4-5000 security camera system and point the cameras towards your employees!