No, I would not consider Tulum to be wheel chair friendly. You might be able to do some of it in a WC, but there are many places where you need to walk up stone steps or goes across gravel paths. The path/road from the entry/parking area into the ruins is paved road, but beyond that you are dealing with way pre-handicape access law building methods. I'm not sure you could fit a chair through the entry passage in the city wall???
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007, Celebrity Silhouette 2013