The only orangutans found in that region are on the islands of Borneo ( part of Malaysia) and Sumatra (part of Indonesia). I have visited the sanctuary at Bukit Lawang on Sumatra, which is get-attable by ferry and road from Georgetown in Malaysia. But I would have to say that it did not seem suitable for wheelchair users. I have no idea about the Borneo sanctuary; but you may wish to contact the travel agency at http://www.goborneo.com/family/