One of my rental properties is located in a low-income area, which presents unique challenges in finding suitable tenants.

You haven't provided us with any information that would help us help you.My recommendation: do not sell a property unless you have a plan to invest it in another property that will perform better, or if selling will move you closer to your goals.If you don't have a firm plan, hold onto it until you do.

Instead, I'd just rely on a CMA (comparative market analysis) of renovated properties in the area from your realtor unless you have local MLS access yourself to run the report. 

We currently have 88 properties in our inventory!

From my experience, success in real estate investing starts with clearly defining your goals and continuously educating yourself through podcasts, books, forums, and courses.

I have a few rental properties in AZ and PA.

Every system you try will have flaws, or you may salivate over a feature that appears in other software.Some familiar names are mentioned frequently: Stessa, Apartments.com, RentRedi, TenantCloud, Innago, RentManager, Avail, Rentec Direct, Doorloop, etc.I recommend conducting thorough research on each app online to understand their offerings, pricing, etc.

Felicia,Look first to see if there are other quads in the area, as your only zoned now for three units, so at minimum, you could probably make this a triplex in lieu of duplex. 

I'm currently in college, but will be home for winter break.

My mother is very interested in learning more about the power of real estate and how she can get in the game.