I have only closed one off-market deal so far and I have probably devoted 200-300 hours to it.

Do you have a certain laptop or tablet or phone devoted to real estate?

First was the benefits of multi-family and the downsides of single family (many podcasts, blogs and forums devoted to this, and based on my experience with SFR I find myself agreeing). 

There are agents out there that will devote their entire career to 3 or 4 investors.

If you want to have everything in your own name, then you just have to grin and bear it for a while - save up as aggressively as you can, devote all your net cash flow to those savings, etc.

Is it better for three properties to take 6 months total to get online, or three properties 1-2 months each at a time, because you had time to devote to ensuring that it stayed on track? 

I can devote my full time without financial consequences and I am certainly going to Sell as a Broker owner as well.

@Ryan Dossey and @Ray LaiI am not short on time per se as I planned on doing this in a few months, however I don't have a ton of time to devote to it right now, so likely I was going to do the entire neighborhood and outsource to ListSource or something similar.

I know there are funds right now offering these types of returns for accredited investors.If you want to devote time and effort you can lend it out yourself or jump into a big multi as others have suggested.  

I'm currently working part-time in NYC so I've got available time to seriously devote to this new business venture.I've got $150K in cash to invest.I'm primarily interested in the central/south Florida markets since, in addition to investing in real state, I've also have a goal to move down there by the end of this year.However, given that my primary goal is to achieve the highest possible ROI I'm open to consider other states as well, provided that I find 'good deals'.