Tristan,
Don't even think about it! It will take you 30 minutes to get to Morning Star Down hill, and up hill 45 minutes to that intersection, I referenced in another post to you. You need a car!

tristan: Marriott Frenchman's Reef is relatively isolated compared to what you might be accustomed to but normal for STT and "downhill" as it were. There are restaurants on property and, on the beach, one casual and one high-end. In order to really experience all that STT has to offer, best to rent a car. Taxi fares add up VERY fast!

The island is only 13 miles long by 3 miles wide which may seem very small but, given the volcanic terrain, seems a whole lot bigger. And the roads aren't built for walking, however stalwart you think you might be. No sidewalks, blind corners and turns, etc.

There is loads of information on this forum to help you out. Just use the search engine and put in key words and you'll soon find that your planning will be incredibly easy. Cheers!

you can rent a car right from the reef's adventure center right in the lobby. even if just for one day ! but you will get a better deal if you book one in advance. a day rental will cost you 40 to 50 dollars a day last min. And i will repeat what everyone else has told you !! you do not want to walk. once you get off the plane and take a taxi to the hotel you will understand!!
have a nice visit.

Thanks for the help. We'll rent a car.

You can take the Reefer ferry from the Reef to the waterfront downtown during the day, can get some walking in there! 😉