I'm not sure what you mean by blighted, but, I would recommend using Listsource for lead generation.

All without risking a dime of your own money.And the advice the other gentleman offered with respect to "SEO" and setting up a website-- you may well go ahead and do that, but good luck getting found easily and, also, trying to 'attract' "ma and pa" note sellers (which is most of what I chase) that way is tough because, in many cases (this is my experience and I've been at this 20 plus years) these note holders aren't very educated as to the type of asset they really own and have a limited or no understanding of their options (such as the ability to sell the note to generate cash).

You'll be generating much better returns.Out of curiosity: where is your duplex and what market would you likely invest in?

If you don't have any money for automated lead generation like Investor Carrot, you can go Driving For Dollars and send direct mail/phone calls/door knocks/whatever

Do they have systems in place for lead generation?

I confirmed this in my local market doing my own testing.The keyword "We buy houses in [city]" is the highest keyword you want to bid for.How many houses I own or how many deals I have done this last year are personal questions I don't feel like answering mostly because they have nothing to do with lead generation.

My question here is two-fold - should we pick a city and then try to build this network, or feel out building a network in multiple cities and then pick a location based on where we can generate the strongest network? 

You need to have a 3rd party realtor query the MSL for your zipcode and generate you a list of recent sale and tally them up (last 3-6 months). 

If only I had a nickel for the amount of times I've heard infinite banking/whole life in the same sentence (spoiler alert: I would be very rich).You mean to tell me that just because someone has a podcast/website and says they have THE secret to wealth generation that they can share for a low low price if I call/email now, that they may be trying to take advantage of me?

@Jerryll Noorden has a lot of good points and I agree that SEO plays a major role in getting you leads, but SEO is not the best or only strategy - there are a few ways to go about getting leads, and every one of them is applicable and has its strengths.As you can see Jerryll is using a platform that helps you generate leads.