If it's just you and the 20 month old, the only real challenge I see might be if you're eating CS (balancing a tray and a 20 month old) and waiting for the handicapped restroom when you have to use the restroom, when I would be out with one or both kids and they were stroller aged, I kept them in the stroller when I went to use the restroom.
My husband used to travel for work when my oldest was that age, one on one with a 20 month old is exhausting because you're always on but structurally isn't hard, depending on the temperment of the kid.
I did a morning at Epcot with a 5 year old and a 20 month old, it was exhausting and hard in the moment but my rose colored glasses look back on it fondly.