There are many different things like investing, construction, architecture, design, broker, management, appraiser, etc? 

I would rather design for the worst case scenario even if the return is little less, as far as return is in the area I expect (or more :)).  

A lot of it would depend on exiting, isle placement, types of refrigeration, full or limited meat department, bakery, etc.Even the large grocers like Albertsons can't estimate a cost per square for a store buildout unless they've designed and constructed the buildings to their specs.Unless you're dealing with an experienced contractor who has built out multiple grocers, I doubt you'll be able to estimate a buildout cost.This type of capital improvement is just to large a component of leading costs so my advise would be to spend the money and have an architect layout the store, they don't need to draw up plans just yet, and then find a qualified contractor, or two, or three, to bid out the job.

I currently work for an architecture firm in Kirkland,WA where I’m involved in the design and construction of Starbucks across the Midwestern States, while also managing tenant improvements.

I'm not an interior designer.  

We use Adam Mazur from Omega Design, he's and expediter in Chicago and he can get good rates on plans

Bill Furlong from HomeAway also spoke on trends in the vacation rental industry, and here were some interesting statistics:78% of vacation rental buyers consider potential rental income when purchasing the home. 77% of vacation home purchasers in 2013 said they planned to rent out their home to short term renters.One third of vacation rental guests are first time vacation rental travelers.More than half of vacation rental travelers are 25-44.Other general trends that HomeAway/VRBO saw:"The rate of vacation home purchases had a banner year.""

His firm is Techne Design + Development.  

Either looking at properties, getting ideas for design, collaborating with others on new or potential projects or just trying to get creative to make a deal happen.

      @Lupe Arredondo           As long as you have an award-winning design and a basement you should be fine.