Can anyone help with tips on how to keep my stomach calm in long early morning car rides?

So back story. I have been diagnosed with I.B.S. this comes after looking into chrones disease for a while. I usually get stomach pain after eating really bad or having lots of stress, which doctors said manifest itself into my stomach. I also really love snowboarding and the trips to the mountain in the early morning have been becoming problematic for me with the stomach pain and also constant stops to try and go the restroom. So my question is this, does anyone have some good tips on what to eat the night before / morning of, any pills to take, how to stay calm. ect. ect. ?? Thank you in advance if anyone replies.