D.S.
We have been doing Kaleidoscope since my son was 2 (he's turns 4 in 11 days) and have never had a "sit down and do an art project" experience! But, that's what makes it great: there isn't just one spot to do one type of project. There are a lot of activities you can bounce back and forth from. My son has some sensory sensitivities so he never focuses entirely on one thing at a time but still has a blast.
I will warn you it is a busy (stimulating) place. There are a lot of colors, textures and environments. If your son does not do well with that, you might just want to be prepared. For us, I like that he can be himself and do a zillion things - paint, color, do glow in the dark wax, look at the big kaleidoscope projected on the walls, dance in the sound area, etc. It is not a Be Quiet environment nor do you have to spend a long time on any one thing.
If you go, have a wonderful time!
Oh, and if your son needs to escape for a bit, the Hallmark Visitors Center next door is quiet and you can watch them make cards and make a bow yourself. Or he can go watch the ice skaters at the outdoor rink. We do those things to calm down.