i personally like driving to cayo, and will be doing so May 18th

. gives us the freedom to do as we like, as the lodges are somewhat isolated. same with the golf cart, but, to each his own.
it shouldn't be rainy season, but i usually take the el cheap-o ponchos that come in a pouch. my theory is that if i DON'T have them, then it will rain. for cayo, bring flashlights.
i never travel without a hat, bandanas, bug spray and mucho ziplocs. as many ziplocs as i bring is usually how many i use. (for wet bathing suits, hot sauce & rum, shampoo, sandy flip flops, sea shells, etc...).
otherwise, bring your sense of humor, and leave your expectations at home!