Based on the numbers, I am willing to bet this is located in 38126, 38106 or 38112.

Celebrate his progress to keep him motivated and engaged.Good luck!

If its the trendy hot areas, or general "path of progress" and your able to make a trip and go drive around to find that "path" its really the best way. 

Philly is your best bet. 

While BP has a rent estimator as does rentometer.com (both allow a few free uses, I believe), I agree with @Zachary Deal that your best bet is to seek out guidance from either the listing agent or a property manager well-versed with the area. 

Like Tarik and Christine.. or than merril or any of the others. its a natural progression and the HUGE money is made selling the information. to be fair and balanced like Fox news.. there are always a % of folks that come through these trainings that do quite well and the money they spent forced them to take action.. its just the other 90% who spend the money and well never really do anything..

It’s great to hear about your progress from flipping homes to turning it into a full-fledged business.

So Real estate is the best bet? 

If I was going into a city and trying to transform a number of blocks I would start with path of progress and work my way out.

Don't bet on passive appreciation, just forced appreciation.