I would give her the standard grace period (whatever is dictated by lease) and then let her know that she is late and you will pursue whatever remedies you have at your disposal. 

I take the standard deduction, so interest on my primary isn't tax deductible. 

@Tim Swierczek helped me get the FHA 203K as the property didn't meet the standard FHA requirements, plus it's a great way to wrap the rehab costs into the loan so you don't have to pay out of pocket.

In this case, the break is available to people who claim the standard deduction, which is $12,400 for singles or $24,800 for married-filing jointly in 2020.The House passed the $2 trillion coronavirus relief bill last week.In particular, legislators are calling for a “partial above the line deduction” for charitable contributions.

Variable rates are pretty standard on commercial loans, @Nate Byers.

I have seen mismanaged properties result in tens upon tens of thousands in loss over and over and over again so much that it's all but the standard.

Any suggestions on a standard lease to use?

I like what Collin said about tightening standards.  

If you are not building in a development, where presales and customization are standard (with large deposits like @Chris Seveney mentioned), why is this a good deal for you?

I have lived in apartment complexes before and have had no issues with fumes, but I am wondering if duplexes/triplexes/quads are held to different building standards than apartment complexes.