Theres probably someone a little closer to you than these guys. Invisible Car Bras - Victoria Australia
I did a road trip to my parent's place (~1200km round trip) last weekend, we encountered a bit of a locust plague in both directions, all I had to protect the cooling system was some fibreglass fly screen. It actually blended in quite well with the dark color of the car, and did save the radiator from being totally clogged with mashed hoppers.
So I feel your concern about protecting your paintwork. Enjoy your trip whatever you end up doing.