For example, I am currently writing my business plan (it is probably 6 pages long) and I have hit stumbling blocks and really dug into the nuances.

My plan is to then get some nice colored envelopes and mass print these 300 or so letters at staples, put them in the envelopes, hand write the address, stamp them and send them out.

I recognize that house because I've got a rental a few blocks away.  

The bidding starts at $17k and it seems like a complete steal considering the fact that every other house on the block sold for 70k or more.

super tough question as a specific area code wouldnt do it since each house varies block by block.

A few blocks to the west you have Liberty Station apartments and a few to the east you have Prince Hall apartments.

It is fairly easy to hold your properties in LLCs if you are using commercial financing, but if you want the conventional loans, lines of credit, etc, you will run into road blocks.

I have a long-term investment property (duplex) about three walkable blocks from an area that was recently upzoned to become mixed used (commercial and residential) with an FAR of anywhere between 2:1 or 4:1 and up to 70 feet in height.

But, go one block away and you can find yourself in a neighborhood in terrible shape that is unlikely to ever recover. 

Feel free to let me know if you run into any road blocks or have questions.