My objective is to make a purchase offer to this tax-delinquent property owner before the tax sale upcoming this Tuesday 12/3/13.

@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. 

The larger ones tend to be more quantity versus quality driven. 5) No warzones.

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.