The common American way of thinking is "bigger is better." It explains the proliferation of liter bikes, big Harleys, and giant trucks and SUVs on the road. I often find that the opposite is true, and that small has its rightful place as well. That is certainly the case when it comes to racing pit bikes on an indoor go-kart track.
Though I've done many track days in cars, I've always been hesitant to do it on a bike, without a steel cage around me. The only exception I've made was for a non-sportbike track day with an emphasis on skills rather than speed. Given decent riding gear, though, I'd be all over this kind of racing myself. The tiny track limits speed in the same way as an autocross, with few straightaways and many tight turns. The bikes don't have any more horsepower than the karts that usually inhabit these tracks, so it's all about skill and maintaining momentum through the turns.
Like most indoor kart tracks, this one is lined with tire walls on either side. You feel it when you hit them hard in a kart (trust me on this), but they still have enough give to absorb the impact if you crash. Similarly, the poles that hold up the roof are wrapped in padding, though I still wouldn't want to hit one of them.
All of the same techniques that work on the big track work on the small one, and are the fastest way around it. It's also quite funny to watch full-grown adults dragging a knee off kid-size bikes. It looks like a scene straight out of MarioKart. With a helmet and leathers, and perhaps a silly costume over them, I'd definitely give this a try.