Travel restrictions?

When were you guys told no more travel? I might plan a trip 14 hour car ride but I'm almost 24 weeks. I am going to ask my OB what they think, just going to visit the husband (I moved to our new town, he's getting out of the army in a month or 2 but I just came up to get settled before hand). I'm having mono/di twins and so far they said everything looks good both with the babies and myself. Also, my cervix hasn't shown and concern for pre-term labor, my blood pressure hasn't risen at all. I am going to call the OB Monday and see what they say but I figured I'd just see what others were told just so I have an idea if it's even possible.