There are numerous sale barns along I 20 that you could stop at. I haven't found one yet that wouldn't let someone lay over for a day. It would be sooner than you planned on stopping, but I bet the Hinds Community College in Raymond, MS right outside of Jackson would let you stop. If you calves aren't very crowded in the trailer and bedded down and hayed well they should be OK to go straight through. If you want to avoid Dallas then don't go I 20 it runs right through it, whatever you do don't get on the loop around Dallas I think its 620, it is terrible 24 hrs/day.