Noooooo way. Even if it were okayed by the midwife/doctor, and DH were willing to stop every hour or so for a stretch or bathroom break, I would not subject myself to that. Sometimes that led to difficult choices because we've missed so many things (including my sister's college graduation and my BIL's graduation from medical school, both of which happened 3-4 hours away when I was over 35 weeks pregnant) but there were way too many cons to taking the trips, and not enough pros.
Being away from my health care provider would be one of the least of my concerns, but it would be a concern. I've had babies born right on time, two weeks late, three weeks late, three weeks early, and seven weeks early...you can never plan for things like that. It's also a lot of stress, a lot of pain in the lower back and hips from sitting in a car for that long (even with breaks), and for me it is very difficult to sleep in a bed that is not my own and when I'm pregnant and have insomnia anyway, I can pretty much plan that I will be completely sleep deprived (and therefore cranky and unbearable to be around) if I'm away from home.