Or a place like Top Golf/Drive Shaft or Pop Stroke? Isn't golf J$ ultimate favorite thing? But at 4-5-6 years old, bounce house/trampoline parks are the place for parties.
I'm just going to say it. J$ knowledge of cars just screams high functioning autism to me. I honestly do not mean that as a bad thing, the kid is very, very knowledgable about cars. But when you combine the car knowledge with the hand/finger posturing and the rolling on the floor and all the other quirks...he needs to be evaluated so then can embrace his differences.
I'm also going to say, and I do realize this 50 year old, old lady speaking here...I don't think it's safe to show a 4 year old that it's ok to hop in and out of the driver's seat of a real car, turn the steering wheel, push on the horn, press the knobs and levers. I do not think that 4 year olds have the discretion to tell this is a a car at the car show, the battery isn't connected, the key fob isn't in it vs this is our car in our garage, that's totally hooked up, the key fob is in the car or nearby, let's push all the buttons. I'll add that my husband, at 4 years old, sat in the drivers seat of his parent's running car, somehow shifted the car into gear, hopped out, fell and ran himself over...so we've always been a little leery of cars with our kids.
