I have created a road trip that would allow someone to hit all the best theme parks in the US (and Canada's Wonderland) in about 6 months, 3 or 4 if you go fast. This is mostly theoretical but you could definitely do a section of it. The whole thing would require some serious cash, though. Here is a link -
Note: I am not finished with uploading pictures and writing descriptions. The route, however, is complete.