Last time my honey brought his own surf rod with him in a rod case. We also put an extra large umbrella in the fishing rod case. I don't know where he got bait.
There's another option to using your own rod. Look at website stmartinfishinginhore.com. This guy has been in SXM quite a while. Also Google "in shore fishing in St. Maarten". There's quite a lot out there. Most posts are a little old but it may give you some insight.
Good luck!