small commerical units in old parts of Milwaukee

[Dan C.]

Would like to hear what other Milwaukee investors think of those small storefronts on busy streets in the old parts of the city.

The reason I ask is so often they have 2 or 3 residential units as well as the small storefront.  

So just imagine a small , 750 s.f storefront on say Villard, no parking, and it has some 2 units, just as an example I made up.  I'm sure you can all picture those, they are all over the place on busier streets in the old neighborhood.

I think often these could be worthless, but I was wondering anybody have any first or second hand experience with these?  Are they hard to rent out and retain tenants?  How much s.f. do you need to have it attractive to convenience store operators? Is it worth it to buy and convert to residential, is that hard to do?  Is it hard to rent out the residential units connected to them, how much less would the rent be then the same unit on a residential street?