Not sure what you mean by the job COULD last up to 6 yrs. Does that mean it's not a done deal and it might not last long at all?
I can't see traveling that far back n forth with your bird for 6 yrs. That's a lot for a bird to have to put up with. Not only that, but you have to think about weather/weather changes too. If you're still having to travel in the winter it gets down right frigid out there..not good to subject your bird to
As for traveling cover cage while transporting from house to car. Move VERY slowly and talk to her the whole time. You might want to keep it partially covered even in the car for the ride, I would. Have 1 perch down low, and no swinging toys/objects. Be sure that if it's a sunny hot day you have something to shield the car windows so the hot sun is not beating on her. Even if cage is still partially covered, sun beating on it would be like an oven.
Tess is right, all birds are different. Some might not mind traveling as much as others. Just do your best to make it the least stressful as possible for her. You might want to get her used to using a water bottle for her drinking water. That way she will be able to drink during transport. Otherwise a regular water dish will undoubtedly spill. She'll need access to water if traveling that far esp if it's hot out.
If everything pans out and he will be working at that job for a year or more wouldn't it be better to rent an apartment and not have to travel? Gas is outrageous and the stress for your bird will be a bit much for yeeears.
Or for that matter even if staying at motel why do you have to commute every weekend? Do you really HAVE to go back home every weekend?