I workout 6 times a week haha), optimistic individual and looking to have enough cash flow to cover my lifestyle/expenses through real estate investing. 

I strongly recommend always keeping at least $200+ in monthly cash flow coming out of a property so your reserves can stay healthy.

This number is the amount of money that would more-than-cover your regular monthly expenses based on your current lifestyle.

They are 4 bed/4 bath units that were built to rent to specific transient (and generally fit/healthy) populations and so only have the physical space for 24" bathroom and closet doors. 

After retiring, you can choose to significantly downgrade your lifestyle and worry about running out of money before you die. 

I also recommend you check out Lifestyles Unlimited. 

If you can figure out the direct to seller model you can make those numbers work easily but if you’re short on time it may take a little longer to find a real deal.To that point last year we picked up an occupied duplex in delco for $53,500 and sold to @Rich O'Neill in your ballpark I’m not sure what the appraised value was at the time but if I had to guess it was ~125-150.If you’re looking in the city for a Duplex you’re acquisition is lower and depending on the area your rents can be pretty healthy with lower taxes.

I am concerned with ultra low interest rates that our demand is not driven by healthy growth, i.e. economic and population, but rather on speculation and low interest rates making debt easier to manage.

There are pros and cons of each submarket but if you're planning to eventually move here, I suggest choosing one where the opportunity fits your lifestyle as well as your real estate investing goals. 

Some may come back, but many will get used to the low cost of living, great weather, & lifestyle.