Tonijim wrote:
Also, are we likely to find a site at that time of year, or should we take a chance to reserve now?
Many thanks. 
Jim
Jim,
  It's the luck of the draw and timing  as to whether you will be able to get a site in April. I'll bet most parks are already full with reservations.  Call Bluewater key  and get on their wait list ( call both .net and .com)   Check El Mar  and Boyd's on Stock Island . You never know when a spot will open up due to a cancelation.     BTW- we will be there for the month of April and I booked several months ago , wasn't able to get a site a Bluewater, so I went to El Mar.