I'd take it right out into the middle of a lake. And to whoever said hotboxing is stupid, yes it is and it's asking to get caught by the cops. Doesn't stop it from being a staple of stoner comedy and being awesome as hell to partake in.
If I could choose anything, it would be a spaceship lol. Coolest thing I ever actually hotboxed was this
I've done that before, it was on a gondola ride down from a ski area. Someone from my group I was riding with pulled out a pipe and some bud. We cracked the windows though to let smoke out, so it wasn't technically a hot box. I was more concerned about getting caught by the resort staff when they opened the gondola car up and smelled the bud, but they never said anything