Personally I was doing Marks on my WHM, got it to 52 this way while I was finishing Main Story on my 60 SMN.
Did 2 dungeons and got to 53, did the 53 dungeon 2 times and guildhest daily 2 times with a few more hunts and I am past 54.
I plan to continue doing this and lvling WHM now that my BOT is 60.

As for queue times, i find my SMN takes just as long as WHM to get into a dungeon since 3.0 opened. (About 5 mins)