If you're visiting each park for one day then you might want to hook up with fastpasses. I'd only recommend then at Alton or Thorpe, where there's a lot to get done, especially in one day. I don't know how most american parks operate fast pass services, if they use a disney scheme then the british parks are quite different. Disney (Paris at least) uses a ticket recognizer to give one fast pass per ticket at a certain time for free. Alton and Thorpe do a deal where you pay something like $25 extra for one ride on everything with no time limit. These can quickly add up though, which is why I'd only recommend them if you're short on time.
PS. Stealth and Rita not included, they have separate fast pass tickets at a lower cost with only them included.