I'm going to take a step further and explain what additions my chain would add to its parks in the first 3 years.
The goal of the company would be to take parks that are/used to be classic old-school parks and let them live up to their potential. Kind of like how Palace Entertainment does a great job at letting their parks keep their history.
The Great Escape - This park already did a great job of avoiding the wrath of Six Flags and it actually has a great atmosphere, so this one's easy. I'd have S&S or Vekoma completely replace the track on Steamin' Demon. Next I would add a Eurofighter, and finally a small, twisty GCI. During these years I'd also slowly do some mantainence on the amazing Comet. Future projects could include a few more thrill rides and eventually a dark ride.
Six Flags New England - Oh boy, now this is a park that pisses me off with its wasted potential. First of all, operations and staff would be the most important part since for years this has been an issue, and it is destroying the park's reputation. So I would make sure the staff is highly trained and the goal would be to put the customers first. Next I would do a complete renovation of a lot of the scenery and theming. This entire year would be nothing but projects like that. Next I would tear down Goliath (even though I'm one of the only ones who actually likes it) and put in a compact Gravity Group coaster. Future plans could be more flat rides, longer programs on the ones they already have, and completely transforming Houdini.
Six Flags America - Completely fix the horrible mess that is Gotham City along with some other minor improvements, get a log flume, replace Mind Eraser with an Intamin Impulse coaster. They also need way more flat rides, and to keep up the good maintanence on the wooden coasters
Those are the Six Flags parks. I'll figure out the Cedar Fair parks I'd buy. Those should be easy.
Top 3 Parks: Knoebels, Dollywood, Cedar Point
Top 3 Steel Coasters: Steel Vengeance, Phantom's Revenge, Skyrush
Top 3 Wood Coasters: Voyage, Lightning Rod, El Toro
Top 3 Flat Rides: Knoebels Flyers, Zipper, It