Will mate,
I ride a midsize 160. I really enjoy the advanced track! I spend most of my time there if not riding with a group on the intermediate track.
Having said that, it's build for bigger bikes so it's a lot of work as Racka mentions. The jumps are very 'supercrossy'. So you would want some sort of experience, and knowhow and a big dose of common sense if you were to ride on the advanced track as the bigger bikes hoon straight past you. And something I only just realised is that you can be out of site to other riders behind you when you are in the middle of the doubles, or on the ends of table tops. Because pitbikes tend to be a lot smaller we are also out of site easier so be careful you basically dont get used as a landing platform!!
I would only suggest you venture out if you are experienced. I would hate to see any accidents, and a banning of the smaller bikes on that track.
Hope that helps.