A handful of years ago, we were traveling on December 23rd, traveling north on I-95. We just passed Dunn, NC around 5 pm and the motor started really knocking. We limped to the next exit and found a hotel, booked a car rental and called around looking for a place to have the van towed to. We were fortunate to find a mechanic open on Christmas Eve. AAA got a tow truck out to us pretty quick, but it was early in the day.
We got pretty lucky that we found someone open. This year Christmas Eve is on a Sunday, so that's a double whammy for you. Traffic on the 26th will be bad, at least on I-95. Being flexible will be helpful. If you break down on the 24th or 25th, you will probably be able to find a tow, but you may have to leave it in a mechanic's lot until the 26th.
-Michael