Well, you've gotten lots of advice, much of it very good. But I don't think anyone has hit on these points yet...
Do more research before you go. Decide, at least to some extent, on where you will go, how long you will stay out, and when/where you expect to return return to "the world". That way you can plan appropriately for food, gear, etc. If you are taking your truck, you'll be able to haul all you need, and that's good. Make sure she's in good running condition!
Once you've decided on where your adventure will take place, you can make the appropriate contacts regarding regulations, accessibility (if native lands/private property are an issue), whether or not your firearms are appropriate for the location and allowable by the regulatory authority.
Let someone know about your plans so that if some calamity befalls you, others will know to come looking. I know that probably seems like a tether to civilization, and contrary to your intent, but the facts are you are young and inexperienced (by your own admission), and your family surely loves you and would want to know - save them the anxiety.
Truth to tell, I envy you the adventure. To me, Alaska seems like the promised land. I can tell you that back when I was your age (30+ years ago), I had a group of pals that I had adventures with along the Missouri/Arkansas border lands. We had great fun backpacking, canoeing, hunting and fishing in that country...we fancied ourselves adventurers, and we were!
Finally, have fun, be smart, be careful, and let us know how it goes.