I'm pretty sure there are already multiple posts with various ways of getting into old ironforge, but the way me and my mate just did it seemed a little different so i figured it was worth a post, I remembered a while back people could use the 2/3 seater mounts to bug through certain walls and we kind of expanded on that, i sat in his side car he did a running jump and did a 180 spin into the kings room so that the side car was through the door where i automatically got dismounted and with very little effort ended up in old ironforge.
Like I've said I have seen different methods using the engineering mount to get into old IF but I havn't seen this one.