We see lots of different ways transactions go to hell in a hand-basket, sometimes through no one's fault, like say you get flattened on the turnpike or a satellite lands on you. 

While I agree with Luke, get your systems in place and you can lean heavily on technology, you will still want someone nearby to check-in on your place, make sure it didn't get trashed between guests, replace inventory (dishes, glassware, tp, etc), make sure there are no leaks, running toilets, broken down AC...

There's potential for more because one of the units is vacant.It's in a satellite city of Orlando metro, about 65-70 miles from Orlando International Airport.

Renters insurance typically is capped at $7500. and covers their clothing, dishes, television... not what you own.

Letters may be more expensive but they tend to get better responses and with such a niche list it is better to dish the extra money to get results.

Same for dishes, glasses, blankets Etc... 

If not you could go either way, I think security cameras will soon become like the satellite dish, you have to let them be but you can dictate acceptable installation.

Finally, I asked the pest control guy what's wrong and he tells me when he got there, there's dirty dishes on the dining table, dirty dishes in the sink, and when he lifted up a mat next to the sink, about 50 roaches scattered.

The sink  for dishes use this other one, clothes use this other one. 

I love everything to be clean. especially in the kitchen, no dishes in the sink etc.. some in my family will not clean unless you are on them.