If she means October's rent, then you will prorate it for the number of days she's there, but she must pay up front.She was given instructions on what to do when it was only restricted to one small piece of furniture and when there was no evidence of it anywhere but on those two pieces of furniture and I'm guessing she didn't do anything AND she kept the furniture with the mold on it allowing it to spread.

Tangentially, there are a fair amount of former STRs now being sold around town in part because of the regs and also saturation.  

Is that why you want to purchase there?

Currently there are a ton of buyers pouring money into finding deals off market and it's tight any where in the country.

Are there red flags I should be looking out for?

There used to be a classified section where people could list properties for sale.

There are no tools that I have found that accurately capture rent trends, its more so just looking at what current rents are in the market and having the experience to understand how much rents have gone up4. $20/month if basic.

There is no way I’d wait 30+days to collect my money. 

There is apparently, a lot of misunderstanding as to what is meant by “hard money”.

This would solve the problem of having to be there daily.