traveling in third trimester

Mommy of Two
When is to late? What has your doctor/midwife mentioned is okay to still travel? 
My situation. Husband is military and is about to have two weeks of. We where planning on heading to our home state which is 12-14 hours of driving including a 25 minute stop every 2-3 hours.  Originally this was going to happen while I was 32-34 weeks pregnant. My midwife said it's okay as long as I'm healthy and no complications. Now there is a little dent in our plans. The leave has been pushed back by a week or two so now I would be 35-37 weeks. Personally for me I think that pushing it. So I would like some input on this. Would you travel at this point. (My baby shower was supposed to be held during this "vacation" but that's not to important to me.) I told my husband he can go by himself since I can go back whenever I like. He can't so I figured at least I can give him this option. He doesn't really like the idea. Can't blame him.