Long-Term BRRRR Strategy Calculator / Calculations?

[Charles Soper]

I'm building out a business plan and working on a long-term strategy that will ultimately provide retirement income somewhere around 15-20 years down the time horizon. My better (and data-driven) half asked a question about what the "end of the road"/start of retirement would look like using the BRRRR strategy and I didn't have an answer. So off I go searching for a calculator of sorts that might help and I've found a few that get me most of the way there but not all the way. Some give me the 30 year analysis on a single property which I suppose i could aggregate and get an answer but it's sloppy, or I found one in the FilePlace that runs out over multiple years for multiple properties which was great, except it excludes the BRRRR idea and and rehab costs.

So I'm turning to the community in hopes that somebody can in turn point me to a nifty tool or make a suggestion that I haven't thought of to arrive at an answer.