+1 for airport transfers as we have had a few nightmares at Geneva over the last few years (like being charged £120 for dropping the hire car back at the Swiss side when it was hired from the French side).
A supply of basic spares such as cables / chains / tubes / tyres / nut ‘n’ bolts would be useful. A few disc brake pads maybe for the more common types of brake.
Access to a good bike mechanic who can also do suspension repairs would have saved me a lot of hassle on our last trip also!
Porridge.
Ibuprofen.
A spare bike to lend out just in case?
Oh and big meals at night!