Melissa - I agree with you that an 8-hour drive seems excessive for field trip for a group of 9-year-olds. I think your suggestion that your H drive is a nice compromise. In your position, I'd certainly feel a lot better if my H were driving than another parent. My D7 being driven by others is something that makes me nervous on shorter trips, so a 4-hour drive each way with someone else would be too much for me.
