@Andrew Millard I'd agree with Nathan G. points, as this could also be another contributing analysis-paralysis element mentally stopping you from jumping into the REI game. 

If you think there is a chance that they will sue, you may want to consider having someone from an environmental company come in and get air samples.

If so and even if not, you need to pay for a phase 1 environmental report.- utilities:  septic, public sewer, well water vs municipal water.  

That element does not factor into a "cash out" loan. 

This is by far the most important element of your marketing mix.

@Terry RoyceFrom a real estate investors mailing perspective there are 6 choices.First Class Hard StampStandard Hard Stamp non automationFirst Class hard stamp automationStandard hard stamp automationFirst Class Indicia AutomationStandard indicia AutomationThe last two are generally reserved for Postcards as a letter utilizing an indicia would have horrible open rates.Here is an example of an Indicia.The B stands for Bundle, T for Tray and the Last number is the Sort Position.The automation aspect of the mail is simply a Bar code, which includes a tracking code, and packaging per guidelines of the USPS using the aforementioned Bundle, Tray and Sort Sequence.An element of non automated mail is that the mail can take up to 30 days to be delivered.

"Without the element of uncertainty, the bringing off of even, the greatest business triumph would be dull, routine, and eminently unsatisfying." - Jean Paul Getty"Most of the important things in the world have been accomplished by people who have kept on trying when there seemed to be no hope at all." - Dale Carnegie"Whenever you find yourself on the side of the majority, it is time to pause and reflect." - Mark Twain

I doubt it would fit the "if I started over" title, but I'd be happy to write on environmental and property condition due diligence.

Mason Valenzuela Keep in mind when sending a mail campaign that there are three key elements to the campaign, The List, The delivery System and the Copy.

In your case, consider dividing the 6,000 into three groups and running three concurrent campaigns with three variations on test messaging (and elements like use of photos vs. just graphics, etc.).