Good advice here.
I eat peanut butter toast or a pb&j everyday for lunch if I have to do something during the day. It stays with me usually.
You don't have to be on Imodium for a couple days before, just take one or two of the pills before your trip in the morning and you'll be okay.
When I was at my worst, but still semi-okay enough to go places, I took a snowmobiling trip with my family. We had to drive to our destination -- 2.5 hours away. Hardly any bathroom stops. We were on the trail, in the snow, in the cold cold woods for the day. By the time I got my snow gear off, it would have been too late to go anywhere, even in the woods. I took Imodium that morning, just two pills, and I was good all day. I even ate a hotdog for lunch.
Good luck.