There's lots to do there!
For cuisine, i suggest trying out these:
http://www.papiamentorestaurant.com/
http://www.amazonia-aruba.com/
There's a lot of good restaurants there, but these two made its mark to both me and my wife.
For sightseeing, check out the:
- Bird Sanctuary
- Butterfly Farm
- California Lighthouse (really, it's just a lighthouse, we only stayed 20m there), it's on one end of the island
- Caves
- Natural Bridge and Natural Pool
If you can, try renting a bike or a vehicle without a top, the weather is usually great down there and there's nothing like driving on and off the city in this manner.
The opposite side of the island (relative to the lighthouse) is not known to be entirely touristy, but there's a nice public beach on that side. It's more "local" in my opinion.
Nearly everyone speaks English, so communication shouldn't be a problem.
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