Las Vegas and the major resorts have done a pretty good job of making all aspects of the city and the things you might want to see accessible to all people with disabilities.
Of course there are challenges, mostly relating to the distances you have to travel and the crowds you have to navigate, but for the most part the resorts in Vegas have met and surpassed all legal requirements.
If you have special needs, be sure to tell the reservations agent about them as you are booking your room. They will be more than happy to assist you in arranging delivery or accommodation of wheelchairs, portable oxygen, electric scooters, and more.
If you'd prefer to do it yourself, there is one company that we have heard good things about. They arrange for deliveries of major medical/disability equipment including motorized scooters to the hotels. It is: