the gal, a hairdresser, was cutting my hair 1 day. she told me they do cash in the envelopes for food, rent, savings, etc. said her dad raised her that way.I thought, "these people should meet dave ramsey!"

Food for thought. 

You will also need to consider that you will need to draw up legal contracts for the events, liability insurance, possibly food and safety/alcohol permits, and a bevy of other things that I probably don't know about. 

No pet food left out, no trash open overnight... sanitation cuts down rats.

But I think I will hold off on house hacking because I am currently living with my parents not paying rent, only my food and light.

It might also be carpenter ants as they will make that kind of noise (like crunchy cherrios) both of these insects could be in the walls and you would never see them inside the homes (even if there are tens of thousands) as they are just nesting there and foraging for food outside.

Food for thought as I don't own any investment properties, yet. 

Food, transportation and utilities aren't cheaper.

We assured them that putting food on the stove and leaving the premises was not acceptable behavior & we'd be following up and they settled down.Good luck!

The example here - our large french-door refrigerator keeps tripping the breaker, so the guests have to go flip it back on or their food spoils.