A lot of professional painters fall short here.

Investors tend to fall in love with certain properties they own, and stick with them even if something better comes along.  

Most of this is about mining your opportunity, not waiting for one to fall in your lap. 

She trapped us into signing the lease as 1) there were no reasonably priced properties to rent & 2) we were not planning on moving this fall, so no money saved, nor household packed.Her property needs new windows because they leak and we have had major water damage, bathroom vents to be installed & mold removal from said bathrooms.

It would be a challenge to get the 1/4" per foot fall necessary to tie into the existing main line on the property, although not completely ruled out.  

The rust belt is defined as parts US (northeastern) that are characterized by declining industry, aging factories, and a falling population. 

Perfect location, in the heart of Falls Church City, 10 minutes away from DC and other major locations in Northern Virginia.

I am seriously considering taking $150k of it and buying 3 new builds $50k down as rentals in somewhere like a Houston TX subburb, Wichita Falls TX, Oklahoma City OK, or Kansas City, MO.

Every GP, real estate investor, makes mistakes, doesn't time the market perfectly etc, looking for the perfect is the enemy of the good. good REITs right now, take a look at ADC - agree realty, does multi-tenant triple net large shopping centers and has better growth outlook than Realty income-O-, 6% vrs 4%, which is also great company, both stand to benefit from low supply of retail space, last 5-10 yrs construction-wise, and thus better rents going forward, and interest rates should fall near term, lowering Cap rates and increasing underlying asset values and sales proceeds (only hold REITS in a tax-sheltered account, 401k or IRA, due to high taxation of the dividends-ordinary income) Good Luck

All  real estate activities fall somewhere on the spectrum, with say owning a real estate brokerage at the extreme ACTIVE BUSINESS line and investing in a REIT index fund on the PASSIVE INVESTMENT line.