Just like in the stock market, real estate investors need to have diversity in their portfolios, must not be over-leveraged and/or not in long positions betting on appreciation.If you have significant equity in your properties and they provide a sustainable level of cash-flow then an economic downturn won't be devastating.

Also, like I said I'm open to foreclosed properties if they also either have occupants or if they have a low sustainable price point.

However, I am trying to think for the long-term, and if I am to meet my goal of 20 properties in 10 years, I won't be able to use my own money to sustain this.

Wholesaling is not easy and requires sustained spending on a marketing campaign to be effective, it also has no guarantee of return. 

I'm in Louisville and building from SFH to multi-family here, but Huntsville will have sustained stable growth for years to come.

Definitely start part-time and don't even think about full-time until you are really, really sure you can sustain it because once you are full-time, you'll have the added stress of health/dental insurance and all other self-employment responsibilities (not sure if your current full-time job gives you benefits...if not, then it's a mute point).  

Because of this it's going to be hard to find a business who does this as it's just not a sustainable business model to do all of that for someone as a regular product offering.

.- Include language in the agreement that states the late charge does not establish a grace period and that all parties agree the charge is presumed to be the amount of damage sustained because of late payment and that it is impracticable or very difficult to fix the actual charge.

I feel like if the asset is leveraged correctly and can be "self-sustaining" (I'm sure that's not a term), then you can move on to the next one.  

It was also more sustainable for me.