Well, I wear a size 26W right now. Hopefully that will be down a size or 2 by our trip. I did have to do the "walk of shame" off the kiddie coaster when I tried to ride with my son. That mortified me into not trying anything else that I wasn't for sure about for that trip. My husband is a skinny thing, so he could ride with the kiddos on the things they wanted to ride.
The link at the website makes it seem like I should be fine on FITH, Lost River and the American Plunge, plus the others I already know about. I'm not worried about the roller coasters, really, although I do like Thunderation, but it was a tight squeeze 8 years ago, before I gained all the weight.
Thanks for all the help!