A shoe store may want a vanilla box, with minimal TI.  

In my STRs, I have a little store at one property with eggs, honey, soaps, etc and that has done extremely well.

I repair them myself (I knock out the cardboard stiles and replace them with solid pine) but the ones right out of the store are pure junk.

Your margins also need to be better on the deal upfront because you need to have reserves to deal with a 6 month eviction process and you need to do a good job of documenting the evidence.With that said I had a mentor who was smarter than me who said real estate in tier 1 cities is the best store of wealth.

been to the grocery store lately ?

When the SHTF You might see gold buyers setting up card tables in front of closed businesses or inside grocery stores buying all forms of gold.

Again, the BiggerPockets store has some books for this or you can learn by watching podcasts, reading blogs, and interacting on the forum.

However, I don't actually care as long as they are not bringing in clients, displaying signage, storing materials, etc.

Materials have to be stored somewhere , usually the last room to be done . 

Is there a local store that sells them?