Disability awareness in the Northern Territory is pretty high and getting higher. New accommodation must meet accessibility standards and discrimination by tourism operators is illegal. Many key attractions provide access for those with limited mobility and sometimes for those with visual or aural impairments; contact attractions in advance.
Long-distance bus travel isn't viable for wheelchair users, but the Ghan train has accessible facilities (book ahead). Some car-rental companies (Avis, Hertz) offer rental cars with hand controls at no extra charge for pick-up at the major airports (advance notice required).
Download Lonely Planet's free Accessible Travel guide from http://lptravel.to/AccessibleTravel.
Deafness Association of the Northern Territory is a potentially useful resource for hearing-impaired travellers.