Hope you have some nice winds for your visit. The thing about Lake Worth and points well north and south to Biscayne Bay and the Keys are waves. The more wind, the larger the waves that come with it. Things have been a bit lighter this year so it may be less an issue. Anyway, if it is huge in the ocean and you are having trouble getting past the shorebreak you may want to consider heading further south. Say to NE 15 St. in Pompano or even down to Biscayne Bay. ASM and Miami Kiteboarding run some great sea taxi rides out into calm, flat, shallow waters in the Bay that work with winds from all directions. With each inlet you pass going south, usually the waves drop appreciably. They have some nice swells off Lake Worth by the way.
Anyway, as to spots. Some guys ride regularly about 1/2 mile north of the Lake Worth Pier near the Four Seasons Hotel. You could park in the public lot north of the pier and walk up. I would advise launching, landing and riding well away from bystanders here or anywhere else down here for that matter. You recall Cherry Beach, there is more than a bit of that going on down here. The good news is the density of kiters in LW is quite low. Another spot is to the south just north of the Boynton Beach Inlet. Watch the tides there as on an incoming tide it really rips inland. It is a scenic place to ride. With most areas here DON'T ride within 100 yards of any beach with lifeguard towers. That should avoid most of the problems. Another spot is further south still, Delray Beach off the south end about 500 ft. of Casurina Road. This is a very popular spot so it can be crowed at times. A good alternate is a park about 1 1/2 miles south. There is just one lifeguard stand there so be sure to stay well away from the guarded area.
I would tune into the weather resources at:
http://fksa.org/showthread.php?p=47650#post47650 to get an idea about what is blowing through before your sessions.
Another area is to the north on Palm Beach. Parking can be dodgy but you can walk north of the guarded area and away from Royal Palm Blvd.. There are some regular kiters in that area. There are lots more spots but that should get you going.
Have a great trip!