Welcome aboard!
I read often about the GB chartering options to Alaska with interest. My boating experience in the US was limited mostly to the Great Lakes - primarily Erie, Ontario and the St. Lawrence.
While living in Europe, I have managed to cruise southern Norway, but the climate there can actually be closer to that of Florida than Alaska in the summer.
So, given the choice of taking my own boat up the coast of Norway a bit into the arctic or, trying to experience something similar on a GB charter in Alaska presents an interesting dilemma. The GB charters, I have read, can be "flotillas" - which is nice if you're working with a boat that you don't know well and are in an area that you don't know well. If I were to attempt northern Norway (think Lofoten Islands) in my own boat, I would have to be extraordinarily attentive to the weather...and possibly consider leaving the boat in a heated building in the north over the winter and returning south again during the following summer. I don't want to cruise during icy weather. I presume a situation like below is possible in Alaska too if one cruises at the wrong time of year...