Thanks for the added info. I'm a little confused now though becasue in your first post, you said you were going to WDW and in the next, you said
Disneyland. I'm a WDW expert (so my whole answer is WDW based), but have not been to DL in a long time.
Four years old is a good age, since she will still be small enough for you to lift her if you need to. My youngest DD is 18 yrs old now. She has CP (mixed type, spastic quad) and is still small enough to do some things, but I have fond memories of when she was little and we could get her on and off things much easier.
You probably need to play things by ear as far as how much walking she does, but keep in mind that the distances at WDW are immense (just around WS in Epcot is over a mile) and most 4 year olds without CP spend at least part of their time in a stroller.
To get into some of the ride cars is a long step up or down, so you will probably be lifting her in and out a lot of rides. Here's a
link to Deb Wills site where she has pictures of ride cars. Most of the pictures don't have the whole car on, I think she was taking them more from the standpoint of how roomy the seats were for "Pooh-sized" people, but you can still get some idea. Here's a
link to a thread on this Board about ride boarding that should be helpful (even though the questions were pertaining to adults).
For leg cramps and general tightness, when DD was little, there were a few things I did at the parks. One was sending her on the teacups with her dad (I can't do spinning rides myself). The spinning motion was great therapy. Another thing I did was sit down with her laying on my legs. Her head (face up) by my knees, her butt at my waist and her legs going straight up my chest. That was a great way to stretch. You can also go the First Aid in any of the parks and use one of their cots for stretching and ROM. We found doing those things helped prevent leg cramps later on.
The characters (especially the ones who are in costumes where you can see the person's actual face) are great with special needs kids. I don't know if they still do this, but Guest Services in each park used to have scheduleslisting the places and times for all the characters. Some of the less crowded character greetings are in places like the countries in Epcot. You should be able to find Cinderella, Belle and Beast at France sometime during your trip. Snow White and the Dwarves are found in Germany, Aladdin and Jasmine in Morocco.
For parking, if you have a handicapped parking permit, bring it along with you, especially if your stroller doesn't fold/unfold easily. The regular parking lots have trams to take people from the lot to the park entrance (strollers or wheelchairs need to be folded to go on the trams). The handicapped (they call it Medical) parking is close to the entrance at the Studio, but it's kind of a hike from Epcot and MK. When you bring your own car to MK, you still need to take the monorail or boat from the parking area to the actual park entrance. For that reason, I always suggest people who are staying on site take to the bus to MK. The bus leaves you off very close to the turnstiles.
For the stool problem, if you haven't already checked it out with your doctor, you might want to see if she actually has constipation. Some people get leakage of softer stool behind the hard stool and that's what makes the incontinence happen. Sometimes a bowel program of stool softeners, bulk medications or schedules of suppositories can help with the problem. To avoid leaking thru clothing,
this is a link to a great product.
Ask as many more questions as you need or feel free to email or PM me (links at the bottom of my posts).