Yes, you can walk to the Boardwalk or you could take a boat.
If you take a boat, make sure you get on the one for Epcot and not MGM, or you'll have a longer ride.
Flying Fish is kind of pricey, however you can cut the costs by splitting an entree. The kitchen won't do this for you, but there is no extra charge for this. We do it all the time.
As for the dress code, you'll see everything from "just from the park" dress to "nice casual" to "dressy". They'll take your money, however you're dressed!! It has wonderful food though....
The most notable in the Dolphin is Shula's- and it's the MOST pricey, too. Everything on the menu is ala carte, and the portions for the entrees are HUGE!!!
Be sure to take a look at the menus at
www.wdwig.com !!
Have a great trip......