The original plan for adaptive reuse was always commercial on the first floor, whether it be office, retail, service related and a restaurant off the back loading dock area.
If this building should become a market with full time vendors on the ground floor, a pavilion type roof, something akin to the old train station platform sheds added to the south side facing 3rd Street could accommodate the occasional and transient vendors for a farmer's market.
Something like this (but obviously in much better shape!)
