Enthusiastic planning delivered in staccato fragments. 何があっても ('no matter what happens') is a set concessive. 海パン is an abbreviation of 海水パンツ ('seawater pants,' swim trunks). The checklist-style delivery (タオルに、海パン。虫除けスプレー！) uses 体言止め throughout — just nouns, no verbs — to convey excited packing energy.