You've received lots of good suggestions to consider. Here are a couple general thoughts that may also be helpful. Enjoy SXM.
1. SXM is small and all beaches are public. Some are more difficult to access than others but that assures added privacy for those that want it.
2. If you choose the French side, some basic French language can be helpful and is appreciated.
3. Driving can be a challenge but attitude and patience can usually minimize the annoyance.
4. Crime exists in SXM as it does most everywhere, sensible precaution with your valuables is important.