Dining Options - Walking distance to Gusman Center, Miami
You could always use the Metromover and head into Mary Brickell Village too. Metromover is the lone useful form of public transportation we have here in Miami. I have heard great things about Oceanaire and another restaurant who's name escapes me but I know there is a "Lolita" involved haha.
The Gusman is a great venue. I saw Buddy Guy perfrom there and it was an incredibly good time.
Ocean Aire Seafood Room
900 South Miami Avenue, Miami, FL 33130
There are not many walking-distance dinner options downtown.
La Loggia is about 3 blocks west. They have decent Italian food.
Il Gabbiano and Prime Blue Grill are in a new building downtown at Biscayne & SE 3rd St. I've heard very good things about Il Gabbiano (Italian) and OK to good things about Prime Blue (steakhouse/seafood).
La Loggia Restaurant
68 W Flagler St, Miami, FL 33130
335 S Biscayne Blvd, Miami, FL 33131
Prime Blue Grille
315 S Biscayne Blvd, Miami, FL