Hi Lic! Thanks for visiting planDisney.
I'm happy to reassure you and your sister that Disneyland Resort is dedicated to being a welcoming and inclusive environment for all Guests, and to that end, your sister should find that she can comfortably enjoy most of the
Attractions the parks have to offer. The only real exception appears to be Silly Symphony Swings in Paradise Gardens at Disney California Adventure Park. Otherwise, Attractions with safety restraints accommodate Guests of many shapes and sizes up to 600 pounds. It's truly a friendly space for all.
Some Attractions are a tighter fit for adults and your sister might prefer to ride solo on these Attractions, but she won't be the only one to make that choice if so! Adult Guests ride solo all the time at Disneyland Resort for many reasons. I took a solo spin on Dumbo the Flying Elephant in Fantasyland at Disneyland Park on my last visit, for example. We were an odd number and I didn't feel like squeezing in. Riding solo, I was able to snap some great pictures of the view from up high over Disneyland Park, as well as pictures of the rest of my family in their ride vehicles. My husband chose to ride solo on Luigi's Rollickin' Roadsters in Cars Land at Disney California Adventure Park for similar reasons. The Cast Members at both Attractions asked us how we'd prefer to divide up our party. No judgment about how we decided to break up the group! They're accustomed to accommodating Guests' needs and wishes.
You will find Attractions with
height requirements for safety reasons, but if you're tall enough to ride, you should be ready to go in almost all cases! I hope this is good news and no one has any anxiety leading up to what will be a magical visit. Everyone should feel free to be themselves in the Happiest Place on Earth.
I hope this helps!
Elizabeth