Allentown and Bethlehem are both great places to invest, both for appreciation and LL friendliness. 

I love the simplicity and user friendliness of Baselane.

It looks like Texas is leading the way in pet-friendliness, which is something to consider if you're a self-managing landlord.

Lots of factors affect friendliness...Fees: Google "All About ADU Permit Fees & Waivers" for a breakdown of these on average by jurisdiction in San Diego County.

Note - DSCR lenders can vary quite a bit when it comes to their underwriting/qualification/overall friendliness towards STRs so make sure you are aware of the differences

No, most hosts in the United States avoid them at all costs, due to the lack of host friendliness.

The downfall I see is the landlord friendliness of the enviornment.

However, I'm still open to choosing Columbus Ohio if it's a better investment than the Philadelphia area.My priorities are:- Landlord friendliness (I don't want to get stuck in a location where its hard to get uncooperative tenants out of a property)- Friendlier Short Term Rental laws (AirBNB, etc) - Ideally lower property taxes (Not a huge concern if there isn't a big difference between the two)- Better cash flow (If the different purchase price to cash flow is substantial, I'd want the better cash flowing area)Which between these two regions would you recommend?

Here's a list of some of the best cities in the country for cash-flow, landlord-friendliness and appreciation

There are several reasons for that including but not limited to, landlord friendliness, lower prices, population growth projection, positive job growth rates, lower crime rates, 1% rule, to name a few.