My method as well. 

We were initially looking to flip homes, which would potentially bring higher immediate cash returns for her enjoyment in her later years, however I’ve been researching the brrrr method as well to generate cash flow without the stress that flip process may cause her.

@Shai Galapo two methods I would suggest here.  

If you want to gather emails and do some email marketing, there's a new company that many hosts have been pretty happy with....Go STR MarketingI will check into this company. i don't think this will be a substitute for StayFI as you still need a better method of capturing data beyond just the contact date you get from your PMS.

Using the next ten years and the snowball method to pay them off.

Not sure if this is the most recent post on land flipping,  but I came across another ed platform -  The Land Method and Land Riches Blueprint. 

Hello Brian, when you own a property "subject to" the existing mortgage and are considering reselling it using the same method, there are several important considerations and potential restrictions you need to be aware of.Due-on-Sale Clause:Most mortgages contain a due-on-sale clause, which allows the lender to demand full repayment of the loan if the property is sold or transferred.

You should just identify your methods. 

She earns points on it, which is the reason she's using Bilt has her rent payment method.

This is the simplest method, but it also means your tenants are more likely to abuse the utilities by leaving windows open with the heat or A/C running, leaving lights on, ignoring the toilet that constantly flushes on its own, etc.3.