2 summers ago when Joli was less than a year we drove from Houston to Atlanta. I think it ended up being about 18-20 hours total. But I planned a stop in the middle so we did about 2/3 one day and the rest the next. [It's always better to drive longer the first day, IMHO].
She had her carseat which was actually fairly new at the time and I gave her toys, but she was pretty uninterested in them while in the car. And we were moving for the summer so my car was completely FULL besides my seat and her seat (even the floor bored on her side was completely full and inbetween us). She handled all of that pretty well. She gets car sick, so I had to make sure I gave her some car sick meds a couple of times. She just curled up and slept for about 90% of the time. The last hour or so she started making very pathetic sounds and it made me very glad we reached the hotel. It was like she was saying "are we there yet? are we there yet? mommy i'm bored. are we there yet? please please please let me out. oh mommy please"
So my advice:
make sure the puppy is comfy.
If you aren't opposed to using meds, "calming" med and/or benadryl is very helpful.
and like others said, plan on adding 1-2 hours to your trip for puppy potty breaks that probably need to be longer than your normal breaks.
And since you are going to see family you will probably have plenty of ouputs for the extra energy on the way there! The drive back will probably be much sleepier!!
