I have been there a couple of times.
the first time I drive up with a truck/camper and used the Alaska state ferry to get to some of the destinations. the total cost for three weeks was less than a one week cruise ship.
the second time we went, we flew to bellingham washington, took the alaska state ferry (with cabin) and then rented cars at some destinations and stayed at bed and breakfasts.
planning is VERY easy, especially if you go to the state of alaska site:
http://www.travelalaska.com/
and of course the ferry site:
http://www.dot.state.ak.us/amhs/index.shtml
just about every city has a tourist bureau, and a lot of time they will send you free maps and discounts.
one funny thing we noticed, when we were in some shops, if you want to buy something, wait until the cruise ship tourists have to leave, all the prices go down as much as 70 percent!
the second trip was two weeks, and once I got the cabins and sailing schedule down for the ferry, a few phone calls and web site visits, and we had everything booked.
stayed at denali park, went on a helicopter tour and landed on a glaicer, etc. etc.
lots of fun!!