My girlfriend and I where just talking about this. We are planning a cross country 3 week trip this summer. Idaho-North Carolina-Vermont-Idaho.
We both will be on bikes I on my 2k and she on her 900.
I was trying to figure out if its cheaper to take a car than 2 bikes.
What I figured out was:
Our average mpg is 45mpg. Based on 2k=40mpg and 900=50mpg average is 45.
So taking two bikes is equal to driving a civic or a hybrid type car.
Neither of us has such a car, we both have cages that would not get 20mpg if you added them together!
The way I see it. We are going on the trip either way. Its a plus that we can save money taking the bikes instead of a cage