@Danielle Jones100+ year old properties are common here in the Maritimes and we have a few.One of our primary objectives is to improve the energy efficiency of these older properties by 40 - 70% {so far they older ones have all turned out near, or above, the 70% mark}.

To address your specific question about sketchy neighborhoods, I would consider using this website as an objective tool. 

A good REALTOR will know the market far better than you, understands the contract, has strong negotiating skills, can be an objective set of eyes on the property, and more.

@Sam Mahmood start by clearly defining and quantifying your objectives.

Also depends on your long term objective for that property or the overall portfolio.

Having unbiased counsel and advice that's aligned with your investment goals, thereby separating any one specific market from your investment objectives. 

Maybe his weirdness gave rise to your input on points 1 and 2 - there's nothing objectively wrong with "hanging out in the common area" or "having guests over."

It will depend on your goals, objectives and business model.  

Between a death in the lender’s family and a vacation this caused another few weeks of delay as a new title search had to be completed on my buyer’s other house being used as collateral.Now we’re at approx Sept 1; All along the way this information was communicated to the sellers as we moved through this entire process and they never once objected or took issue with the unforeseen delays.

I think I could handle living next to tenants for a year or two if this option is objectively better.