@Quincy Adams I strongly agree with the perspective of @Jason Stutenroth. You do options for opportunities such as section 8 or just renting directly to tenants. Of course, I would imagine class D neighborhoods have a higher risk for vacancy (however you have options to drop such a risk). If I had to predict areas that will grow in appreciation in Harrisburg...They would include midtown, areas along the Susquehanna river(scenic area with running paths), Harrisburg train station area (central hub for transportation with plans to grow), and Cameron street (industrial area seeing a slow revamp). Moreover, other areas around Harrisburg that I would say are desirable are Mechanicburg, Camp Hill, Linglestown, Rutherford, Hummelstown, and Hershey.
Jason, if you ever have a free chance to speak I would GREATLY appreciate a discussion about your investment experiences in Harrisburg. I am local to the area, and also seeking to establish a rental portfolio.