My wife has a lot of motion sickness trouble. Dramamine is required for every plane flight. Some rides are bad, multiple rides in a row are usually worse. So, we take our time and don't do all the bad rides at once. (e.g. we ride Rockin' Rollercoaster first thing in the park, and then usually sit quietly or walk slowly to another part of the park until her stomach settles again. Tower of Terror right after is NOT an option.)
We also enjoy cruises, and dramamine alone was not suffucient for a particularly rocky January trip one year. After that, she went to her doctor for Rx patches, aka Transderm Scop, aka scopalamine. They work *wonderfully* for the cruises. A patch lasts 72 hours, and they can be replaced at that point. She has no trouble on the ship, or the flight home after. They definately work, and work well. The downsides are: dry mouth side effect the whole time you use them, minor withdrawl (strong fatigue) when you stop using them, and they are expensive ($20 copay for 4 patches on her insurance, $40+ for the same on mine, since they are considered non-essential drugs). So far she hasn't tried using them in the parks, we just prefer to take our time as I said above.