I would quarrel with the words "miracle run".
The Rangers aren't a terrible team. As you say after the poor start that had a rather good record. The goalie is superb. The D is outstanding. The forwards probably block more shots than most teams.
With that said, I believe the Rangers played team at their level (Philly), a team that struggled against Columbus, and team that lost it's starting goalie. Kudos to the Rangers for putting themselves in a position to get into the finals. Good Luck never hurts.
Assuming no further injuries (and assuming the rangers do get into the cup finals) to the oppositions starting goalies/est players are the Rangers a deep underdog to win the cup? I think so. I believe the PP is still weak, the offense is spotty, and the team takes too many penalties. Will the total team effort/bonding lead to a cup? Anything is possible. As I said this isn't an impotent team. They are simply decided underdogs. The good news... they have been decided underdogs since the start since the start of series 1. If there is a next series We'll see if the pundits truly underestimate this team or we simply watched a good team encounter some luck?