But we are happy that we are getting positive cash flow so long term wise we should turn a profit.A month later with one house under our belt as experience, we paid all cash for a 4 unit multi-unit.  

You already have a head start with 6 under your belt.  

We're in the Rust-Belt, which tends to be very isolated from the sometimes brutal nature of the 'hot' areas to invest in real estate.

That depends on how good of a deal it is and where, but if you already have a few deals under your belt, connect with as many people on bp, meet them locally, chat them up, and they might be able to help you fund some more rentals. 

Lastly, each person has to be active and has to have at least 2 deals under their belts.  

Keep grinding but always keep reading and adding new strategies to your tool belt.  

Get your first deal under your belt.

I currently work in IT but have several years of construction experience under my belt and hope to utilize the experience in RE.I flipped my first property last year.

Now that you have a condo under your belt, my advise is to go bigger4,5,6,50 units.

I would think using the 401k loan could be a good source of short term funding if needed to tap into to snap up a good deal, but waiting until you have more experience under your belt is a good notion.