There is no legal restriction on theme parks (there is on professional sporting events). I have never visited the Holy Land Experience so cannot comment on that park directly, however the remainder of the parks in Orlando including all of the Disney parks, Universal parks and Seaworld prohibit carry by their rules (not enforcible under the law) and all of them DO search bags upon entry.
In all cases if you are discovered you will be asked to leave the park premises and may find yourself "banned" for life. Return to the property after such action, armed or unarmed may result in an arrest for trespass.
I have written many times about the danger of park carry, because of the unfamiliarity of the "backstop" in that so many walls in these parks that look like stone or other solid objects are actually stucco and styrofoam and it WILL BE YOU who winds up responsible should you fire a shot that injures someone on the other side of one of these walls even if you are stopping a valid threat on this side.
The Orlando theme parks do a great job of security in general. They are so much of a target for so much more than simple nut jobs that their security is really about as sophisticated as it gets.
As noted, however I cannot vouche for the Holy Land Experience in that vein, although I would think that they would consider themselves way up there on the potential target list and respond appropriately.