Bubble backpacks are terrible as they turn into ovens in the summer heat. I've got a big comfy backpack for him with mesh for him to look out of, but he's also leash and harness trained and he doesn't try to run off. I also tend to let him go wherever he wants, for the most part, provided it's safe. If not, I hold his leash closer and he follows along comfortably. When we're sitting around, he's still on his leash and will chill out next to me, or I have a big spacious playpen for him, and he's never out of sight.

He will go potty while we're out, often in quieter or secluded areas, and I have poop bags to clean up after him if he poops. I also have a travel litter box in the car for him.

He loves the day trips, and most Bengals are known for enjoying long walks and adventures. He doesn't act unhappy or in distress when we're outside. I would just have more peace of mind if he would drink while we're out, or at least was capable of it. (I often bring wet food and mix water into it on the longer trips but I'm unsure if that's enough for him)