I've seen rental units get leased with iPhone photos that have good lighting. 

The build cost would be a little higher because i would use foam in the exterior walls and also use insulation in the interior walls for energy saving and sound dampining.

Can you shed more light on why you need this money?

Tread lightly.

The market seems to have a lot going for it with the beach, the lively downtown, the historical appeal and the night of lights draw during the winter months.

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There was also a failing retaining wall in the rear of the property that completely blocked natural light form a handful of houses, and was technically on the property line and a shared responsibility.

If the property only needs light cosmetic updates, 3 months might be doable, but for more extensive renovations, it’s going to take longer. 

But if I wanted lights and refrigerator etc, I had no choice but solar, this is why you're correctly alluding to the rural aspect.... 

First impressions matter and presenting a property in its best light can attract potential buyers and increase its market value.