I don't eat much Korean-style noodles so I will let the other folks chime in.
For tofu places, I like BCD Tofu, like the other poster said. Also, I have been to Seoul Garden and Chodangol, both are decent too. I haven't been to Chodangol for a while so I don't know how it's doing recently. The last few times I went to Seoul Garden, the food was a little inconsistent but I might give them another try.
for tofu it would be BCD tofu house. my fave is the pork tofu soup. their seafood soup isn't bad either.
as for noodles you need to specify what kind of noodl dish you're talking about. if it's naengmyun you're pretty much out of luck since nowhere in ktown does it any good. kalgooksoo is awesome at arirang.