The key is to be unafraid of the fantastic. Dare! Logic need not apply to your adventures as much as sheer, fantastic awesomeness should. In fact, do not hesitate to go the extra mile and mix up ideas; for instance, The Golden Voyage of Sinbad featured a cyclopean centaur -- not because such a creature existed in any myth or previous story but because it looked cool. So you should be unconcerned about any convention but the one you're really emulating, and have free license to mash up monsters, myths, legends, locations and cultures.
A word of caution, however: "Camp", defined as "an aesthetic in which something has appeal because of its bad taste or ironic value", is best avoided. The source films are not silly. Rather, their outlandishness is earnest and presented as a vehicle for drama and excitement, not as laughable absurdity.
