The show is about 45 minutes long, from seating to leaving give it about an hour, it's so worth it too. It's such a good show!!!! For PS we got there about 15-20 min early but not more than that. For regular seating we don't even get there that early actually, we like being on the Mezzanine level personally.
Yup, there is an elevator. They only allow those in scooters/wheelchairs to use it as far as I can ever tell, everyone else has to trek up and down the stairs.