Advice for first time (6 hour) road trip with 5 y/o, special needs 3 y/o, and 2 y/o?

So, to start, my kids have never been in the car for longer than an hour. I'm no stranger to road trips myself as my dad works in the oil field and starting in toddlerhood, my younger sister and I were in the car for multiple day drives several times a year. However, my kids have never done it before. And while my 5 year old is as laid back as my sister and I, my 2 year old is NOT.

My 3 year old son is special needs (severe autism, nonverbal, receptive language of an 8-12 month old). My nearly 2 year old son is just.. well, a handful. I love him dearly and he is the cutest little guy ever but to be honest, calling him a "Holy Terror" is putting it nicely and mildly. He's rough. And I will be about 11 weeks pregnant to top it off.

I can't do electronics/tablets and the like because the 5 year old and the 2 year old both get carsick. I got carsick as a kid too and I remember my Gameboy and similar electronics making the nausea worse. So no electronics. We are going to try to get up early that morning but leave around noon so that the holy terror (2 year old) naps for some of the drive.

Mainly looking for tips for the 3 y/o and 2 y/o. 5 y/o is easier because he likes to color, likes to play with playdough, is conversational, likes looking at books, playing with stuffed animals, etc. He's an easy fellow.

But my 3 y/o does not like coloring or playdough. But he is very visually stimulated. He will sit for hours looking at certain images (especially of the number 2) so please drop any ideas books of visually pleasing pictures, pictures that include words, numbers, and signs especially.

But the 2 y/o? I'm at a total loss. Likes coloring at home but I know him well enough to know he will just scream and throw the colors in the floor in the car. He doesn't like looking at books. Any ideas on how to entertain him? I'm going to attempt to sit in the middle row between him and the 3 y/o but I still get carsick, myself, if I am not in a front seat so I may not last long there.