In these 7 days of insane roller coaster, we managed to arrange some hard money for financing, set up an appraisal to estimate a property we hold for the purpose of the loan approval, arrange an inspection, meet 2 contractors and crunch the rehab numbers so they make sense, find out that the lender can not 100% finance the deal as hoped, get discouraged but somehow, on a late-night phone call arrange some cash from a family member, and all that only to discover a day before closing, that the seller had $140,000 of liens against the property..The deal fell apart. 

I've noticed that, in reality, while demo expenses are a big part of it, oftentimes people severely underestimate the other costs involved, like getting everything drafted/designed properly and getting every part of the construction permitted by the City.My overall point was that demo costs are more predictable and foreseeable, whereas people that consider demo and rebuilds oftentimes underestimate the other costs involved, which tend to add up to so much upfront cost that demo/rebuild projects end up being a not-so-great investment decision after you crunch all those numbers.  

FSBO w/ owner financing.Lets assume the numbers work on my initial number crunch and its a good cash flowing property.The main house of the property was built in 1920 and at some point a long time ago it was split up into 4 units.

From what I keep reading they state that agents, brokers, property managers, etc are major resources for finding data that I could use/crunch to determine property value more accurately.  

I am willing to work for knowledge and experience whether is demolition, painting, number crunching, or just getting coffees.

You can't say that until you've crunched your numbers.

Credit and Liquidity Issues so when the nation's banks face a credit crunch, often caused by a higher prime rate, its profit margins and cash reserves can feel the pressure, resulting in decreased lending in the overall economy, and consumer spending. 

No way to know for sure until I take him a specific deal and sit with him to crunch the numbers.

I probably won't be buying anything for another 2-4 years, so right now I just want to learn how to analyze deals at least to the point where I can tell if something is obviously not a good deal without spending a lot of time crunching numbers.

But, basically you need to get with your sister, get her on board, then crunch the numbers.