There are restaurants closeby but I feel they will be closed by the time you get there. Your best bet will be to eat at the airport before heading out to the airport. There could be a bar or two that might be open within walking distance and it is safe over there near HI Rosemount.
Having stayed there for concerts, many do walk. It's not far and probably faster than driving as traffic will come to a near stand still. No shuttle that I'm aware of. If you drive allow 45 to 30 minutes!