As Jay mentioned, my first trip on the Inside Passage was in 2000 in a 17 Boston Whaler "Montauk." It was a great trip, with no mishaps, but marginally comfortable. Would I do it again in the 17? ...probably not, but that has to do with comfort rather than safety. (But B/W now make a 19' Montauk - Hmmm, that might be Fun!
As previously mentioned, I think a few items are paramount:
(1) do NOT do the trip if you're under a time constraint (but that's also a factor in a larger vessel as well). Being able to take your time makes the trip Much more enjoyable, and you can wait-out bad wx and not feel pressured into going out when you shouldn't.
(2) be thoroughly familiar with your equipment. Choose what you want to take very carefully. Certain items may be nice to have, but not really necessary. Frankly, planning and anticipating the upcoming trip is a large part of the whole experience. Plan carefully, but don't overload. Be comfortable and safe, but some items simply are not unnecessary.
(3) Once you've identified your cruising equipment - take a long shake down trip. Outfit your boat just as you planned for the IP and see how it works out. You may very well make some adjustments. (In my case I took the Montauk to Lake Powell and spend a week going up to Hite then a week back. It was time well spent.) One of the items I found that I needed was an extra couple of books ... getting layed-up for wx can make having some extra food and a good book much easier!
(4) This relates to Item 2. Know your vessel, motor, fuel system quirks, refueling from can's, anchoring, sleeping aboard (I didn't beach camp in AK). Know your fuel consumption/range with accuracy. For trip's like Jay and Jolee have done, you may actually NEED that extra 60 gallon's of fuel. If you need it fine; if not don't bother with it (but make sure you have a comfortable reserve).
(5) Do a LOT of "map reconning" beforehand. Have an idea of where you want to go, the distances involved, and research where you might find backcountry floats to tie-up-to, good anchorages, etc. Read everything you can get your hands on beforehand, make notes.
(6) When you get to Ketchikan, reward yourself with a "Seattle burger" from the Burger Queen, and take it across the street to the Arctic Bar and eat it with a cold Alaskan Amber. Say Hi to Paula (the owner) but don't be offended by her language. She's ...aah, colorful. Seriously, occasionally reward yourself when you're in town.
(7) Lastly - Have a GREAT Time. While in Juneau I met Renee Hemingway-Douglas (author's of the Excellent IP cruising guides.) They were very gracious, and commented (from the bridge of their NordHaven...) that "...the smaller the vessel; the greater the Adventure."
As you get closer to your first IP Adventure please begin another thread on C-Brat's (or PM us directly) for other specific ideas. LOTS of C-Brat's have spend time cruising the whole area, and I'm sure they'll have and endless list of things to consider in the planning. (Again, pre-trip planning can be darned near as much fun as the trip itself.)
Best,
Casey