I looked at that excursion, but can't do 5.5-6 hours. Even with travel time, that is way too much time in the sun for me all at one time. I have a horrible time with sun stroke no matter what I do. Have you ever done any of the city tours? The one says there is a 10 minute shopping stop, so, that made me think that shopping might not exactly be safe or the best to do there.
With Princess cruises I did the
Best of ....tour, it was very good, the city is very compact, we went past the fort and up the hill to La popa, great views up there, and you can look down over the port and the Magic, a bit like the view in St Thomas from above of the ship, this is a nice place to view, Then the fort, and then a walking tour of the old town, a bit hot and humid take water, and its on different surfaces like cobbled stones, this is a few years back, then the coach took us to the shops and we went emerald buying, be careful again, as you would consider these good value but on valuation at home in London there wasn't any bargain just normal cost price.
Its nice to see, but a very hot humid day. I love the little colorful buses around the town.
Beaches in the town are rubbish, you have to go out of town.
What about the Mangroves tour, its long, but very good,