Lots of questions need answers to get good advice. As stated by Kim I never heard of Portico. Give us the exact place you will stay and then someone can give you info about restaurants in that area or close by.
Lots of great places to eat all kinds of foods so having a car is good. I go to SXM just to eat great foods! The beach is second for me. If it's a beach with great food so much the better.
If it is Pourto Cupecoy where you'll be staying, there's a Medeteraen, a French, an Italian, and Altro a mixed food location that offers a fixed price dinner. Also on Sunday at Rendezvous restaurant they have live jazz. Make a reservation if you plan ti eat there. But you can hear the music from Mama's Italian or the Medeterean restaurants since the group performs outside.
If you go to Grand Case there's a place named Ocean 82 that has great seafood.
Like others I would go to Tortuga instead of Sunset Beach Bar. Tortuga's prices are better, seating on deck to watch planes or out on the end of the beach. I would not walk anywhere at night. Drivers are crazy, crime is on the rise. We don't where any jewelry because we've seen it ripped from people walking and off the go on a scooter.
I'd recommend Leslie at Kenny's car rental because of the convince of pick up right there and not after driving in a bus off airport site.
.
