Help with Layover in Aventure to Sobe

[dx052]

We are travelling from the UK and want to go to South Beach within our layover before we go on the cruise the next day. We arrive in the afternoon & will be staying at the Turnberry Isle Miami and was wondering if there is a bus that goes from their to South beach? Is it far, how much would a cab cost for the return journey if its quite late & by that time very tired? I once took a bus from South Beach To Aventure mall but that was quite a few years ago though & I can't remember much.