HI there,
I have a season pass, so have already been three times this year. I try to go right for rope drop and head out by lunch time, as it gets busy pretty quickly.
I would try to go midweek, and not on weekends or holidays. Go STRAIGHT to Wonder Mountain Guardian. I went on it on Saturday and it is amazing! But the capacity of the ride is very low and it is very popular as it is new. We waited two hours, and it was worth it, but if you want to ride it and only have one day, I would go there straight away. It is a small coaster, shooting game (like toy story mania) against a screen, and the ride tells a story. Plus it has a shocking ending (I won't ruin it for you

)
The other rides with large line ups are Boo Blasters (although they did change the cars in the offseason to fit 4 people instead of 2), which is a shooting game like buzz lightyear, and the line ups get really long.
The Fly (similar to goofys sky school in California) also gets long lines, and don't miss Thunder Run. It is a small fun coaster in the mountain, but it cycles the track twice each run so only one train can ever be on track at once so it gets very long lines.
Stunt coaster is also fun, but with a lower capacity so I'd ride that early too.
The big coasters of Leviathan and Behemoth are popular, but I find the lines for those never get terribly long, because the capacity is high. Especially Leviathan because it fits 4 people across.
The water park is also really fun.
And there are also some great shows!
I'd definitely take a look at a park map and figure out what your priorities are, and set a plan to make sure you hit those first! Good luck and have fun
