The guest house brings in about 2,200 per month on Airbnb and the studio that I created makes about 2k.

[If others disagree, I'd like to read why].So if your motivation is purely to maximize your current investment, perhaps find out how much the cheapest fixer-upper small studio, in as worse a neighborhood as you could stomach, in as far a radius from your work as commutable, would cost.

There's a ton of bars, parks, restaurants and yoga studios that you can walk to.

@Nicholas Sambrick In addition to those mentioned, I'd add The Real Estate Rehab Investibing Bible by Paul Esajian, and Real Estate Wholesaling Bible by Than Merrill (even if you aren't planning to wholesale).Also, @brandonturner published  "The Best Real Estate Books for Your Investing Business " on BP which might be helpful.I find audio books work best for me on the way to and from work.

I think this could be done for less than 100k and would likely yield at least a 800sqft studio which should bring in about $900/mo in my market.

-Units are same sq ftg (approx 500 sq ft), but one is a studio and one is an actual 1 br-Fully renovated (floor-to-ceiling) units of the same layout and size in the complex are selling today for $155k-$180k (big range, but supply and demand, right?)

It does give me the opportunity to listen audio books and podcasts.

Jason, it is an alcove studio in Battery Park City (so a doorman building) and while there have been minor repairs (replacing broken appliances, spot repairs to the parquet floors), as far as I can tell the floor, bath and kitchen are all 80s originals beyond those small updates.  

I personally have been very impressed with the per sq ft returns on really small units too (like studios on the beach).

In Atlantic City, there's a Yoga Studio that's been holding some great events for the area that involves social justice, developing the area, etc.