Another suggestion is to look at the trips offered by Adventure Caravans or Fantasy.
Check out their itinerary and then do your own thing. It will give you ideas of where to go and things to see.
We have traveled to Yukon/Alaska 6 times on our own with never a problem. Lots of things to see and you just need time and more time to make it a leisurely trip. We have also traveled the Alaska Ferry System 3 times and got off at various ports along the way. Doing this takes a lot of planning though as you want to travel in daylight so as not to miss anything.
Good luck - start your research now for a great trip.