Well, All I know is that Nxd2 leads to a HUGE advantage for white.
Is there anything?
Sort:
If there was a knight on g2 and Bh3 blocked out somehow (2 black pawns on h3 and h4, but unrealistic), then Kc5 would be disasterous =D
Kc5 d4 Kxd4 and its back to black's turn, with zugzwang =)
RyanMK carry on 
Well, looking further, it appears as though white can force a promotion (or two) after Bd3xa6. I'm pretty sure that must lead to a forced mate.
This would also be intresting =D
Umm... wait. Is the knight on a3 or b3?
RyanMK, give us a diagram, how? after moves of things like Bc2 and Kxd7, Bd3 and then finally Bxa6, and if the knight doesn't take, how can you promote the pawn? all the rook entry squares are protected well.
knights on b3, the diagram up there i just came across while thinking, thought it would be intresting. but yes stick to the original =D
Is there anything White can do to take advantage of black's closed position immediately, or can he only advance slowly?
Question: is it
A: There is something immediate
or
B: White can slowly trample black down
or
C: Neither, White will gradually VERY slowly gain material