Hi Jennifer! Thanks for bringing your question to planDisney.
Unfortunately, Disneyland Resort
policy doesn't allow the type of collapsible seat you're describing. It's better not to try to get it through theme park security and end up having to take your stool back to your vehicle or hotel or surrender it. That would be a not-so-magical start to your day.
However, a long day of walking and standing on pavement can wear a person out! I have some tips for how to beat the exhaustion. First, plan breaks in your day. Whether it's a trip back to your hotel for a quick nap or a dip in the pool, a mid-afternoon break can really revive a person. We also always plan to sit down for both lunch and dinner, taking plenty of time to refuel and rehydrate.
Mobile order your food from select quick-service dining locations using the
Disneyland mobile app and find a shady place to enjoy your meal or book a
dining reservation at a table service restaurant and get off your feet for a while. I'd also advise avoiding new shoes. When you're choosing what to pack, be sure to select a supportive pair. If you can change shoes later in the day, you'll get some relief too. Plus, there are plenty of benches and quiet spots for a quick rest. We recently enjoyed a little people-watching on a porch on Main Street, U.S.A. in Disneyland Park, and you'll find pleasant spots like that throughout the parks.
Hope this helps! Have a magical day.
Elizabeth