The ship leaves you right in the heart of downtown. Walking around the shops is easy but can be seen in a short time. If you want to do more in Nassau than walk around you need to get transportation for Atlantis or a beach.
Just exiting the ship there are shuttles offered at a great price for either downtown (5 USD round trip) where they drop you off at a market or to the beautiful Altos the Chavon (7 USD round trip). You can do both trips if you want. The place is very nice, easy to navigate plus the people are really really nice.
Ohhh Curacao is sooo beautiful. Like a mini Amsterdam in warm weather with vibrant colors. It's easy to walk to the main attractions. Probably the best port of call in the Caribbean in terms of architecture. Loved it!
In Aruba you have to go to Eagle Beach, it's only a short taxi ride from the port and it's one of the best beaches in the world. The white soft sand leads you to a calm sea of pristine clear, warm water perfect for swimming.
Aruba is also great for shopping from high end to cheap souvenirs. One of my favorite ports of call in the Caribbean.