I've had Type 1 diabetes for about 30 years. I rode the Alaska trip from Cincinnati to Alaska and back solo. If your diabetes is in good control when you're not touring, you should be OK for touring as well. The risk of being wrong is higher, of course.
I didn't refrigerate my insulin. I had heard a while ago that it loses about 1% of its effectiveness for each month that it's a room temperature. I'm not a drug rep, but that rings true in my experience. I've not a problem with the insluin being useless or having insulin out of the refrigerator being "too strong."
Leaving it by its lonesome in your Givi case on a hot day is another story.
Definitely wear a medic alert. You'll need it if you can't speak for yourself. I do that all of the time anyway as a place to hang my pump when showering.
Bring scripts from your doctor of all of your medication. It helps when crossing the border, it helps when you need supplies. It just simply helps- if you never use them, fine. If you needed them and don't have them, it's a problem.
Been to six continents and type 1 diabetes and travel has not been a problem.
On a non-diabetic Alaska note, I'd strongly recommend riding up and taking the Alaska Marine Highway back.
Good luck. It's a cool trip- definitely gives a "last frontier" kind of feel.