Are they used to the car? I would try several shorter trips.. even a couple 4-5 hour day trips with them to try and break them in. That way you can know ahead of time what problems might come up. Also, you don't have to take all six at once this way at first. Are you going to have six separate kennels? Are you going in a car? That's a very long way!! I have no problems with Bassett in the car, and I've taken Tilly on a couple short trips in the car to try and break her in too. I'm leaving on Tuesday for central Oregon, which is a 9 1/2 hour trip I will let you know if I have any new tips after that!