Man how this aged!

At your age I would start with a primary residence and house hack a small part of it for STR.

During a social encounter, I unknowingly interacted with an individual who misrepresented their age.

If we need to hire someone to mow the rental properties lawns or maintain websites, I am not sure why it will be very hard to convince IRS that we could hire our own kids to do the job if they are capable, and their payment is reasonable for their age.  

With distinct A, B, and C areas, there aren't any truly bad neighborhoods for investment.

Census.gov will give you (for any city/state) the population, median home value, median household income, median age, racial distribution and more.

My response to a few:@Kevin S.The rate of appreciation varies by location, price range, property type, property age, and other factors.

They share a personal account where only rental income is deposited, and I am listed as the beneficiary of their accounts at their bank.Although this is technically a personal account, we still like to refer to it as a "business" account to internally emphasize the necessity of maintaining a clear distinction between these funds and other personal accounts.

Both were able to leave W2 jobs at ages 37 and 40.

First off, congratulations on saving such a significant amount at a young age!