As far as stops, the roadside rest stops are fantastic for toddlers! And, since you will have the dog, both of you can take short walks.... some of them have playgrounds, also. The paths (depending on the kind of rest stop) would be great for your little one to stretch her legs, and work off some of her stored energy....
I prefer leaving early in the morning, but I'm a morning person... I do just fine early morning, but once night hits, I start dozing... hubby is the opposite, though.. and would rather drive late at night, and gets frustrated that I fall asleep on him, when he wants me to help keep him awake!
I don't know what kind of car you have, but can you put her car seat in the middle of the back seat? that way she might be able to see you easier.. I realize this won't work if you have a van, though.
Talking to her, singing to and with her... all of those are good ideas.... if you have CD's of kid type songs, those might help keep her attention, especially if you usually sing those kind of songs with her. When we did road trips, we had several cassettes (yep, long ago!) of kid songs, and we all sang the songs... that is what we listened to then.
Good luck.... it isn't easy, I know.... we were 12 hours away from our family, so I know what those road trips are like! (btw.. when we moved... we moved with a big dog, 2 cats, and 4 kids, age 9- 6 months... but we turned it into a 2 day drive instead of 1 long 12 hour + drive... but my M. and brother helped us move, so we had 3 vehicles driving down, and plenty of distractions. I had the baby, 2 cats, and my M., hubby had the dog in his truck, and my brother had the 3 older kids in his van... still quite a trick, especially meal stops with the pets.)