BRRRR works in my market if you buy an absolute steal from the seller.

Since you’re still figuring out where to invest, look for areas with strong rental demand, good schools, low crime, and potential for future growth.

I think if you can nail that down you will be able to find a market easier.As a buy and hold investor some of the things that were important to me when deciding on a market were landlord tenant laws, price to rent ratio, housing demand, ability to build a team, large population 500K plus, multi-family availability and some other factors.take the process step by step and you will be fine. 

* Does it significantly affect rental demand, vacancy rates, or rents?

Amid surging demand for apartments, the US rental market is contending with the largest supply of new units in four decades.

Airdna will give you a good estimate of the demand for the area.

We've helped a handful of investors maximize their investments over the past several years and anticipate a robust demand if/when the tax cuts are re-instituted. 

How is the demand for that?  

Demand remains strong and rents continue to climb.Great place to invest in rental properties!

so are you doing this work for the seller for FREE.. ???