From Disney World's web site, the dress code for Narcoossee's:
Dress Code Guidelines:
Men: Khakis, slacks, jeans, dress shorts, collared shirts. Sport coats are optional.
Ladies: Capris, skirts, dresses, jeans, dress shorts.
Not permitted in dining room: Tank tops, swimwear, hats for gentleman, cut offs, or torn clothing. While T-shirts are now allowed, the policy remains that T-shirts with offensive language or graphics are not acceptable.
To get there from AK: There's a resort bus to GF (not sure if it shares with Poly or Contemporary, but it should be labeled anyway). I'd also use the resort bus from DHS. From EPCOT, I'd take the monorail to TTC and then switch to the resort monorail and take that to GF. From MK, take the resort monorail, but you can also take the boat launch if you have the time.
DH and I are eating at Narcoossee's for the first time on our upcoming trip and I am looking forward to it. I've read many good reviews, so I think it's worth trying. Have fun!
-Dorothy (LadyZolt)