You need to take your time, with a 7 year old in tow(sounds like you have a great little travel partner) there's a lot you two can do visiting this destination.
I've never done one but there are great island tours on St. Maarten at the end of the tour they'll drop you off and wait for you at a beach. Other than Orient most beaches are pretty close to the port. No worries.
If I were you I would book a nice tour for the two of you and forget it.
Have funπ