A "deed of trust" is a security instrument. 

I have a lot of friends still in the area and a great property manager that only charges 7%, so it feels secure. 

I know you mentioned potentially a larger security deposit or paying six months rent upfront, but I have a feeling holding her to different standards than other tenants might cause you some issues based on information I have studied (I haven't finished the course for my real estate license yet and I'm no expert or attorney), but better safe than sorry!  

Understanding the economics drivers of the market can help you understand the type of people that are looking to rent in your market (i.e. pay you rent once you buy a property).After knowing and understanding your market & analyzing deals on a regular basis, you'll begin to understand how the process works of making an offer.

Now $685 was from damages that I could deduct from the previous tenant's security deposit.

It is not required, but you will have to be able to segregate for taxes.Many states also require that a separate bank account be used for the security deposits.Read your tenant-landlord law, get educated, you need to confidently know your processes.

I opened a series of new accounts for my property. 1 for the combined rental income and 1 for each security deposit.

I read city council notes regularly, and in my opinion there will be new Airbnb rules for the city.

I might also recommend a security camera to catch people trespassing and if/ when they tear down or damage the fence.

Damage, to replace vinyl etc, is likely to be relatively small of 200-300 dollars.Would you fix it, and then keep the evidence to take out of their security deposit when they choose to move out, or would you confront them with the evidence, and post a bill for the amount of the work?