If you want to be steps from the beach and all that Siesta Key has to offer Turtle Beach State Park is for you.  Turtle Beach is a very small campground which is great if you don't like a crowd.  The sites are really close together but we were there to enjoy the beach with our grandsons so it did not bother us.  There is so much to do or do nothing and just relax beachside.  We love to explore so having a free trolley that stops close by the entrance was a huge plus.  Rentals are available across the street for water fun.  If you don't feel like cooking there are two fun restaurants  across from the entrance that offer seafood and other fare.  Turtles roamed the area and each night the seabirds put on a show.  Very hard to get a space here so plan far ahead.