First of all congratulations on being in a position to retire; that does not come easy these days.
As far as gated communities walking distance from the beach there are plenty to choose from in Jupiter, Juno, North Palm Beach(intracoastal not ocean) and Singer Island. I would encourage you to visit my website http://www.servingwestpalmbeach.com and search for yourself, my site gives you access to the entire MLS. Search in zip codes 33477,33408, and 33404 or use the link below.
From the website you can request information about specific communities and propertiesand we can narrow it down to a short list of properties to look at.
There are some great buildings on the beach in Palm Beach. My recommendation would be to dicuss your needs with a licensed agent like myself who will listen to your needs and focus on properties within your budget.
Please feel free to call me at your convenience.
Herman Real Estate Group
Juno Beach and Jupiter have one and two bedroom condo's with in walking distance of the beach. Some are gated some not. Also Singer Island has many condo's on the beach and across the street it is a narrow long island.
For more information on these areas please contact me