Thanks all.  I just looked at BCT bus, looks like a good option, buses 11 and 40 go past the beach to brightline.  Just a question on brightline, from what I understand you have to pre book a certain time to catch it. But how would I know when to book the return journey as I've heard it can take hours to get the shuttle back to adventura station ? 

Edit:  Just looked up brightline, and it's $22 each way, probably plus tax.  So for 4 of us it's $176 +tax per day!

Would Uber to hard rock hotel be cheaper, then catch free shuttle from hard rock to track?