Just beginning to do homework

If you like the comradery and social aspects of a tour, or really don't like planning things for yourself, then that can be a fine option. Otherwise, I'd generally suggest doing the trip on your own as you'll be able to choose where you want to spend more or less time and what you want to see, rather than what the organizers think is best. You'll also have the option if you desire to stay at some smaller and less-developed (and often less expensive) campgrounds, such as state parks or boondocking sites, of which there are quite a few in Alaska and the northwestern parts of Canada.

Two weeks to drive an RV from the east coast to Alaska round-trip is really pushing things.

Here's a rundown of my trip from Vermont to Alaska a few years ago; maybe it will be helpful for your planning and dreaming. I had an absolutely fantastic time.