I rode with my son and we were fine. Getting in is easy, the ride was comfortable, but getting out was a bit challenging for me.
I used to tip the scales at 6' 536 lbs. I could ride comfortably on every attraction except Splash Mountain where I had to ride solo. Movie theaters were a little different, but every theater has some seats without arm rests or with bench seating to help if needed. WDW is very "Pooh" friendly.