I would suggest the Holiday Inn Marina Park Hotel. It's right across the street from Bayside Market, so it's very convenient. While it is perfectly safe to walk from that hotel across the street to Bayside, I don't know that I'd venture out anywhere else at night. We've always stayed at that hotel when we've sailed out of Miami, and highly recommend it. It's not too pricey either, depending on time of year. When we went in May, we paid $53/night and that included breakfast.