Or maybe it is cheaper by that point to just finish the demo, teardown the house all together and rebuild from the foundation up?

Again I know nothing of your market nor any details of the house just working with the limited info I have.For point of reference Nat average to rebuild is around 200-250 a sqft probably more now with all the construction going around around the country.

My current thoughts of what I could do to it:Get some portion of it habitable, or move a camper on site, or rebuild carriage house on property... make it my primary residence.Rennovate along the way.Get it in decent shape and take out a HELOC on the property for a handsome sum.Use heloc to finance pretty much any other flips I wanted to do.  

Rebuild Credit & FICO Score.

Community rebuilds it.

I may have to rebuild the block wall between us, but the neighbor has no fence on the east side.All thoughts and ideas welcome.

The house would need to "fit in" pretty well.It is a good enough deal where I have a fairly hefty rehab budget, which is why I'm considering this.Also, at a certain point, can it be cheaper to rebuild completely than try to contend with a remodel on a dilapidated house?

Rebuild Credit & FICO Score.

Tearing down walls, rebuilding structures, and all sorts of other "fun" (read: expensive) stuff.  

Oh, and it's getting to the end of it's useful 30 year commercial building lifetime, so you might need to teardown and rebuild soon.All the sudden you have a ton of extra expenses and some real risk about what ROI you'll end up getting on your property, despite the cap rate.