For the mobility impaired, Malaysia can be a nightmare. In many cities and towns there are often no footpaths, kerbs are very high, construction sites are everywhere, and crossings are few and far between. On the upside, taxis are cheap and both Malaysia Airlines and KTM (the national rail service) offer 50% discounts on travel for travellers with disabilities.
Download Lonely Planet's free Accessible Travel guides from http://lptravel.to/AccessibleTravel. Before setting off get in touch with your national support organisation (preferably with the travel officer, if there is one).