Hello Tammy,
Thanks for stopping by planDisney with your question. Looks like you're headed to Walt Disney World just in time for some ghoulishly good fun! I hope you are planning on attending
Mickey's Not-So-Scary Halloween Party. It's one of my favorite ticketed events!
Although there are height requirements to keep guests safe, I don't believe there are weight restrictions for any attractions. Having said that, some attractions may be a bit uncomfortable for Pooh sized or Baloo sized guests. I know that getting in and out of
Space Mountain in
Magic Kingdom can be a little tricky, because you have to lower yourself into the ride vehicle, and there is limited leg room. The restraints on
Seven Dwarfs Mine Train are a bit uncomfortable as well. On attractions like
Big Thunder Mountain Railroad that have a lap bar restraint, a larger guest may want to avoid sharing a seat with anyone who is significantly smaller in size, so that the lap bar can fit comfortably and securely; asking to be seated alone is also always an option.
On attractions with seatbelts, like
Test Track in
EPCOT. Larger guests will want to pull the seatbelt out fully before getting into the vehicle. You can always tighten it if needed, and seatbelt extenders are available as well on most of these attractions.
Some attractions like
Avatar Flight of Passage in
Disney's Animal Kingdom have a ride vehicle outside the attraction. Take advantage of these and test for comfort before you get in line. Although this is an individual ride vehicle, the restraints secure you in quite tightly. I've seen people of all sizes ride the attraction, but it's good to know what to expect in case there may be any issues.
Hope this helps. Enjoy planning your magical vacation!
Diane