Will a good concrete company have access to the necessary equipment to grade and dig to prep the site or is it customary to have to rent that equipment for the concrete work to be done?

Research any surface prep you have to do especially if your floor is not concrete.

They then said I would have to still go on and modify any long term blocked calendars thus defeating the purpose of a good solution.  

Acclimate the flooring in the room for a couple days, clean the floor well, don't put it right on concrete, don't do anything the manufacturer says will void the warranty (like adding on any additional adhesive agent), don't install in areas that fluctuate in temperature a good amount throughout the year, etc. 

Ideally you'd want within a few blocks, maybe no more than half a mile for the comp to be accurate

@Carolyn Guertin investing in Detroit should be done on a block-by-block basis.That's actually difficult to do, so we ranked 104 of Detroit's Neighborhoods on our site as Class A, B, C or D to help investors make better decisions and NOT get ripped off.NEVER try to invest in Detroit using zip codes!

The problem is these are automated values that don't factor things in like views, condition, or even if one block of homes sells for more or less than another. 

Just so you all know, my brother was blocked by a moderator (I wonder who), but wanted to convey his response here (see below). 

In this county there was only 1 McDonalds that close and it closed to move a block away at a traffic light, from there former location in the middle of the block not at a traffic signal. 

I own out of state as well, but it's a blocking and tackling, hands on, dirt in your fingernails game if you want to earn the return to make it worthwhile.