To answer your last ? first. The ferry runs about 80 bucks+out of Houghton. There is also a ferry out of copper harbor but have never taken that one. The Houghton ferry is alot larger and wont rock and roll as bad. I have also taken the plane serveice out of Houghton airport. You might want to consider it . I know it runs alot more but the boat ride out of is 6+ hours , by seaplane 45 min. Whats your time worth???
I prefer the seaplane You scheduale not theres . Thats the nice part.
As far as what time of the year to go, I think thats alot depending on what type of weather you are looking for. Opening weeknd in May is Cold but doable. As the weather turns warmer in June the black flies come out when you get inland . Not a very pleasent exp if you happen to be there when they come out. I have been there over the 4th of July and it was 37 degrees. I was there in late July and the weather is warm(high 80's) but you always get a cool breeze off Superior. My favorite time to go is in the fall. Geting cool ,sweatshirt weather, leaves crunching beneath your feet, and with the leaves gone , the whole island opens up to a veiw that you wont ever see in the summer. Fishing on the inland lakes has always been good the times I have gone. I have Caught many pike on chicken bone while watching the moose feed on the shoreline. Not a better sight in the world. Cant post websights on the link , but if you want them email me..magooo2@yahoo