The short version: Looks like you live in Allentown, so invest there.
I'll define Allentown as the Lehigh / Northampton county areas. Overall this has been my favorite out of the four major areas I've invested in (Georgia, Louisiana, New Jersey, and Eastern PA). Landlord / tenant laws are very reasonable, and there is strong economic growth in the local area. There are huge numbers of jobs here that pay $25 an hour, which based off a 40 hour work week, make tenants qualified for a $1,350 a month apartment. Aside from Easton, code requirements are pretty reasonable.
I've looked at expanding to NJ, but the landlord / tenant laws and higher taxes are a killer. Most of my clients are from the NY/NJ areas and come here because of these things. I've looked at expanding into the Wilkes Barre and Scranton areas. That looked like it had great potential, since purchase prices were significantly lower. Appreciation there is low, rents are low, and assuming maintenance as a fixed cost (for example, a hot water heater costs $450 from Lowes in Allentown, $450 from Lowes in Scranton, installation takes the same time, and labor costs aren't all that different), the ROI isn't great. I'd need three times as big of a portfolio to achieve my goals up there. Yes, I could scale up quicker because of the low costs, but I'd much rather have a smaller portfolio of higher-profit units.
If you intend to self-manage the property, I'd immediately cross out everything that is more than an hour drive away. I have inherited quite a few property management clients that were formerly self-managing remotely. The belief that "no one takes better care of my own properties than myself" is commonly held, as well as thinking that the extra profits would help them scale up quicker. The reality for many is that life gets busy, the half-day trip to the property is difficult to cram in, and that property management is tough. One bad decision can kill the profitability of a unit for years.
What happens when someone needs to be there for a rental inspection, or for the utility company to inspect a meter - do you go yourself? How much time do you spend, and what is the value of that time? What happens when a tenant needs to be evicted because they are running a car in the garage and causing carbon monoxide poisoning to the tenants above it? What happens when your tenants call you and say "I think the neighbor below me died, can you do something?" Or one of my favorites... the tenant reports the roof is leaking. Three roofers all tell you that the roof needs to be replaced, but you are skeptical. Do you walk the place yourself, and realize that all the contractors are wrong, it's that the top floor tenant has four puppies that are peeing everywhere, and it is urine coming through the ceiling? That one walkthrough by my maintenance coordinator saved our client over $10,000.
Welcome to the forums David! Keep these questions going so we can help you be successful!