At the same time do your own research and decide in what grade of properties you want to invest in, and the risk tolerance you are comfortable with. 

Mid grade finishes are 30-40/sf less.

It is probably just a matter of how the square footage was calculated.  1590 square feet above grade is almost exactly what 2100 square feet with 2 floors above grade and 1 floor being a basement is.

My 12th grade son just finished his SAT and he will have one month off from school in December.

To get a more accurate quote for engineering costs the perimeter grade beam of foundation needs to be exposed (soil removed) to be evaluated... this is where I'm at right now.

What grade are you in?

Purchase price: $220,000 Cash invested: $20,000 3Br 2 Bath townhouse we purchased for long term rental. 90s/2000s builder grade inside nothing special but was ready to rent with a little paint.

Another solution Ive strongly considered is...installing a french drain some 4ft below grade, and then extending my roof out a bit.

You do small amout of rental grade rehab to be all in for less then full price.  

The other would be what if you didn't add the bed/bath and you went with rental grade everything, could you get this refi'd and hold longer term?