I was on in 08 - but imagine not much has changed. Each place is somewhat different. Most NCL based excursions the buses etc. get fairly close. Some taxi's stands are also close. If you are renting cars (which we did at every port), there is some hiking to get to the shuttle bus stops. I'd bring the brace - better safe than sorry. Just getting off the ship can be a hike! LOL Have a great trip, we really enjoyed ours!
Alright .... A little slow here POA = Pride of America, right? Depending on the dock you tie up to, you could have a hike of anywhere from 1,000 to 2,000 feet. So, yes - a brace, or even a cane might be a good idea.
I worked on the POA and the Pride of Aloha when it was cruising Hawaii. Even though the ship comes right up to the pier in most ports with the exception of Honolulu and on Kaui you do have quite a walk from the ship to where the tour bus or taxi is. For the most parts as far as taxi's go they allow one taxi at a time close to the pick up point. When that one picks a people up they signal another taxi up. It normally runs quite smooth.
The tour buses pull up fairly close to the buildings but walking through the buildings can be a long walk. In other words a cane or brace might be helpful. You can request a wheel chair out to the pier or back if you wish. I helped many people get a wheel chair ride to and from the ship while I worked on her. Just check with the purser when on board and they will be glad to tell you how to request one. You cannot take the wheel chair on a tour but it will get you to and from your bus or taxi.