Colossus is indeed still one train operation, and painfully slow at that. Most rides were walk on/5 minutes today but Colossus had a 45 minute queue at one point. I'd head there first, that's what I did and it saved me so much time today.
Yeah Colossus, Saw, work your way round to Inferno and Stealth and then do Swarm later on because the queue is usually less in the afternoon (compared to first thing)