It really depends on the circumstances. Are you talking flying or driving? Many airlines will not allow a pg woman on board past some arbitrary date now (34 weeks?) - you'd have to check with the airline. It also depends on your health, if you're having any problems, whether this is your first, and whether previous pregnancies have run to term or come early.
I did a trip at 34 wks pg with DS. 4-ish hrs in the car each way. It was uncomfortable, but tolerable. What really sucked was that all that time in the car (I was driving) set off swelling in my feet, which stuck around until he was born. I hadn't had any swelling up until then. And being in a hotel room, dealing with restaurants, lines and the like when I just wanted to lay down and put my feet up really sucked. But, there were no contraindications to the trip.
Follow Mothering