If the former then it could be a good move, if the latter than my opinion is bet on yourself and keep buying SFH's!

., from a C to a C+, or all the way to a B?  

I would say C+ or B-.  

It makes no sense to put in all this A grade stuff in a say for example C or D neighborhood.

Maybe I'm missing something that makes Pittsboro a bad area, as I haven't looked into it deeply, but If you are thinking about placing a bet on growth over the next ten years, then it could be worth investigating. 

With $40k you will be in a C or worse neighborhood.

The deals in Houston are there, but not sure BRRRRs are there unless you are willing to buy in class C or D neighborhoods.  

I can also get solid, 7%+ returns with a couple of oil and gas companies and bet on rising energy prices, but I'm separating stocks, REITs, and notes from real assets that I'm purchasing.

Also keep in mind most people that are boasting their rate of returns don't seem to be saying if the properties are Class A, B, C, or D.One of the things that I do is look at my portfolio as a whole, I have brand new construction in Class A areas, in addition to Class B, and Class C properties.

You can't bet on that, so make sure the property flows a bit at the very least and focus on letting tenants pay down your mortgage for you.