Assuming that the appraisal is accurate, there's nothing wrong with this.

One thing I really do recommend is talking with an experienced attorney to get an accurate idea of the exposure you face.

Is there a more in depth guide or explanation on the ins and outs of these calculators and how to gather accurate numbers instead of just copying what Brandon does in his sample analysis's?  

Is it pretty accurate?

It also seems like a huge risk and gamble to invest in a property without doing an inspection, but it may pay off big.

At best they'd say, "that's not investing, that's gambling."

Property Tax) is accounted for accurately, or is this something I should be verifying and plugging in manually?

He wanted to list at 159,900 and I thought 139,900 was a more accurate price.

I've read some articles on this, and it appears to be accurate.

It’s not going to be perfect, and would just go off general averages, however, ai highly doubt those averages are refined enough to get down to niches, such as a home on the lake vs a home four or five blocks away will likely have vastly differeing occupancy rates.I use its general averages as an indicator of whether or not I want to even bother with an area, if I decide to I then go in and find direct comparable homes and gather data from those ones specifically to create a much more accurate projection.