Beach towns are lovely for work right up until the Wi-Fi drops ten minutes before a call. Before booking, ask the host for a recent speed test screenshot, check that the listing has a proper table and chair, and find the nearest coworking space as a fallback. Many beach towns also have a rainy season that changes everything, so check the best months on each city page.
A backup connection is the single most useful thing to bring. A data eSIM from GigSky or Airalo can run a hotspot for a few hours if the router fails, and it costs far less than a missed meeting.
Many of these towns are an hour or more from the airport on slow roads. Pre-booking a private transfer with GetTransfer or intui.travel saves haggling on arrival. After that, most beach towns run on scooters; BikesBooking lists monthly rentals, which are much cheaper than paying day by day.