Help Planning activities for a 10 year old boy and 13 year old girl

For my mom's 50th birthday, my family is taking a road trip along the East Coast to hike, visit beaches, and stay at Wi-Fi-free inns.

I have 2 younger siblings (a 10-year-old boy & 13-year-old girl ) who don't always get along and are pretty attached to their devices.

I was hoping to give each of them a small travel pack of pencils, markers, tape, and a sketchbook to encourage them to engage with their environment, doing texture rubbing or things like that I remember from school.

My usual approach is to create games or competitions, but they are often competitive, which often leads to disagreements.

If anyone has advice on simple tasks or objectives to keep them interested and motivated, or on projects to do on the road, it would be greatly appreciated,

Sincerely, and anxious older daughter