@Jordan Hanks - Some companies including Evolve Vacation Rentals charge 10% for booking and marketing, with extra fees for cleaning, re-stocking, etc.

Id look at high yield CDs, money market accounts, dividend stocks, bonds or something like that. 

I actually don't like the idea of paying off a property either though, I think one of the biggest reasons for investing in real estate instead of the stock market is that real estate is setup to use debt as leverage.

I have thought about this too as their are stock market games but I have struggled to figure out to make this a dynamic game with risk and finding deals.

Pre-recession stocks were flat for a decade-ish plus.

This is definitely one of the best ways to build wealth, I wish I had put more into this rather than stocks at an earlier age. 

The max Uncle Sam allows is 50k if you haven't taken a TSP loan in the last year.I've seen both good and bad experiences with this but at the end of the day it's no different from any other type of loan, you are just your own bank in a sense.The downside or risk is that you lose your job, your property isn't cash flowing, are unable to pay back the loan, and your retirement account suffers since the loan essentially turns into a withdrawal.The upside or best case is you have the loan for less than a year, your BRRRR pays off the loan, and you pay yourself interest 5% interest.The opportunity cost is if the stock market goes up 20% and you were only paying yourself 5% interest you'll miss out on the excess returns. 

To be honest I would spend more money and get my 1% on North of Baltimore.You should be able to get more than 1% around 21213.FYI, Baltimore in general housing stock is old, when you do moderate renovation like paint, vanity change, new carpet etc... you will definitely have plumbing issues along the way.I would strictly do section 8 in 21213, you can end up in eviction court pretty often othewise.

Rather, your IRA can invest in real estate instead of being limited to investing in the stock market.  

An "investment" like owning a stock is completely passive and has no expenses for you to write-off.