I'd say you'd be missing out big time to do the Inside Passage without a dinghy. Poking around in places where you wouldn't take the big boat, and also walking on shore, can be lots of fun. You can get to places where with a bit of a hike you have a tremendous view. Or just rowing for the fun and exercise of it (also for the entertainment of the dog, who thinks dinghy rides are the greatest).
If you can't envision where to put one, you might consider an Avon Redcrest. It's a really tough hypalon boat, weighs 40 lb, and deflates to a rolled-up cylindrical package maybe 3+ feet long and 2 feet in diameter. The foot pump that comes with it will pump it up in a few minutes. Mine sits rolled up on the motor box in my cockpit, and the oars live on the cabin roof, velcroed to the rails along the side.
Mine's 11 years old, has seen quite a few barnacle-covered beaches, and yet is still good as new. I've had to patch small holes twice - both my fault (fishhooks).
You can put a little fiberglass motor mount on the stern (it's rounded - no hard transom) and use a 2 or 3hp outboard. Mine's a 2hp Yamaha that weighs only 22 lb. With two on board, it goes maybe 5 miles at 3 knots on the quart of gas in its built-in tank.
I like rowing, so I bought a good set of one-piece 6.5 foot oars. With just me and dog aboard, it moves right along, almost as fast as a kayak. It'll carry four people in a pinch (800 or 900 lbs - I forget).
There's a picture in my album.
