Then perhaps stREITwise which does office (can be a good investment but also can be more volatile in the downturn).

Although I am close to Baltimore as well, that is an entirely different market that is more volatile (in terms of recession) than DC. 

. * The US Dollar is at risk to Hyperinflation* The Crypto Market (whether you believe in it or don’t) is not only in a bubble territory but is a highly volatile segment * 0% interest rates would also diminish the impact of central banks’ “printing of money and buying of debt assets,” and could also spur “real interest rates to likely rise because there will be disinflation or deflation resulting from lower oil and other commodity prices, economic weakness, and more credit problems.”

So just know that there's a lot of volatility, especially in some of the more outlying areas.

I use Vanguard's Prime Money Market fund currently paying 1.71%: https://investor.vanguard.com/mutual-funds/profile/overview/vmmxxI previously used a bond fund and found the price volatility wiped out the interest I earned. 

@Geren Williams, seems like a location with steady growth and little volatility.

This area in general is following IPO Tech boom and Nasdaq volatility, If nasdaq is reaching ATM new set millionaire is added and supply o less than 8 S per zip code is taken pretty quickly. 

To be overly cautious you should probably consider increasing your required return on your equity on these projects too because the income stream is more volatile than a higher class property would have.

There's no daily volatility and a 15% growth in value in a year is like a stock increasing 100%.

You would have to be ok with the volatility involved, but after 15 years or so you'd likely come out ahead of if you'd just payed down the 30 year in 15 since the returns would likely be more than the 30 year interest rate.A more conservative approach may be short term corporate bonds or TIPS.