@MJLonghors, I think the guys on here have given you a great deal of sound advice and important information to consider. I get the impression you haven't truck camped much in the past, just my impression from your comments. I have a couple suggestions.
One is to do some practice camping with a truck camper before you make your purchase. Even a large truck camper can be challenging for a novice to properly equip for an extended stay in the camper, like an Alaskan excursion. You are going to be pushing every limitation with the setup you are describing and one thing seasoned RVers will tell you is that it takes a considerable amount of experience to know what you need to take along for a long trip, but more importantly what you don't need to take along. Universally most novices take way too much gear and struggle with overloading their RVs.
Secondly I think you need to change your approach to one of minimizing the size/weight of your camper for the sake of improving your driving experience to and through Alaska. Your original plan of getting a Tremor is pretty sound as the Tremor is designed and equipped to handle the harshness of the journey you are planning. Not that a 450 won't do a fine job, but unimproved roads are far more suited to the Tremor than a standard 450. The Tremor will take you to a wider range of destinations than the 450 will, as long as you don't overload the Tremor.
Keep in mind you are going to push every system in your truck to the extreme in this journey. You don't want to be driving a rig that is maxed out in extreme remote areas with little experience. Underloading and having extra capacities in all areas would be a better way to go. There are numerous campers on the market that will give you plenty of room at a considerable weight savings if you look around, and you'd be surprised how much less camper you can comfortably live with once you get a little experience.
To put it in a nut shell, you are going to experience break downs and difficulties on this trip no matter what. The more you max out your truck and push its limitations the more likely your trip will be an "extreme" adventure. If it were me I would design my rig so that when I pull out from my home, the truck has ample extra capacity in every way to handle anything Alaska can throw at me, including extra gear for breakdowns. FYI tires will take a real beating in Alaska, and help isn't always available.
Not trying to discourage, just trying to help a fellow enthusiast to strike out with eyes wide open. Good luck!!
