What's the catholic/encompassing/general term for these travel essentials? 'Travel items' is wrong; they refer to actual physical objects. 'Travel necessities' is also wrong; they technically aren't mandatory for travel. To wit, what are some nouns that can replace all of the bolded:

Could I please return to you about attending your ceremony only after you decide where to hold it? I ask because the availability of hotels, flights, car rentals, .... might prove unavailable by the time of my booking.