We always do it at the park. Busch can be really hit and miss if you even need them. I would say its about 50/50 for us and we visit about 8-10 times a year at various times. I would never book them in advance if you were aiming to get there for rope drop. You can def do the big ones before it gets packed out, which it rarely does. My cut off limit is a 15 min wait. Anything over that we buy quick queue. If you are happy to wait longer, you def won't need them.