Potty training

I started potty training a few weeks ago and it wasn’t successful so I left it until today, within half an hour he had a poo! So he’s definitely ready, I’m just unsure how to continue this out and about, I know taking a travel potty in the car and plenty of spare clothes but I’m unsure about situations where I don’t have access to a toilet, we’re going to a racetrack to see monster trucks in 2 weeks, I don’t know how to prepare as the toilets will be far and I can’t just whip out the potty in the middle of the crowd 🤣 do I use pull up pants or is that going to confuse him?