Nice job!  

Philly is a nice option, but you have to study the blocks for about a year to be sure you understand the area you are investing in.

A scenario like that would likely result in getting your entire investment back upon refi and also a nice cash-flowing rental to manage.   

If your product is nice, I believe you'll attract the right kind of renter (factory worker, lineman, etc). 

To add to @Ashish Acharya, I would recommend using your retirement funds for notes that earn a nice interest rate, if you're into self directing.Given that you want to purchase a short term rental, I'd highly recommend not doing this within an IRA/401k. 

my hope is to get a nice unit for my son at below 50% of retail.  

on my drive around Lake G  I topped into a new development  Large lots nice Modern Farm house designs much like what I build in my developments but definitely next level from what we build and prices were not bad I think under a million.. 

If it does you have zero asset/income, a much larger debt secured by your personal residence, at just the time you probably also lose your job due to economic conditions, and all those nice folks teaching you about sno ball, infinity, you’re your own bank, etc., will be long gone.  

It is a nice safe long-term spot if you're approaching it with a more long-term traditional real estate mindset.  

I would have to assume that if they've had it that long, they could absolutely have some really nice cash flow going.