It's worth a visit to your local music shoppe to procure some little doodads & thingies to put in your instrument case & soak up any excess humidity. Larkintheam has such doodads, too. & you might want to get some extra strings, & instrument polish & put a polishing on before hand--then when you collect your instruments, a good buffing & change of strings if needed & removal of "dehumidifier" gadgets & you'll be in decent shape to play right away! If the instruments are to be indoors in an airconditioned environment, the excess humidity will be likely removed by the air conditioning system. If the possibility exhists that some nosy persons or childrens' curious hands might open your cases, consider exactly where in someone else's home to leave the instruments.