I've been a Type I, insulin-dependent diabetic since 1962 (can that really be 46 years??). Summer trips can do serious damage to and compromise the quality of the types of insulin requiring refrigeration--specifically, levimir and lantus, both of which are 24-hr. acting, basal insulins usually taken before bedtime. Two small freezer packs (portable icemen) go into an insulated zippered bag with the insulin, and manage to stay quite cold through the end of the day (I usually bury the bag in the middle of some clothes in one of the saddlebags to help insulate them during hot weather). The freezer packs get re-frozen in each night's motel refrigerator (those who camp might do best staying in organized campgrounds with a refrigerator/freezer available). The Novopen with my Humalog Lispro fast-acting insulin goes into a smaller, insulated bag without any ice packs (unless crossing the Mohave at high noon), and gets thrown into the tank bag along with the blood-sugar test kit for easy access before each meal.
All insulin-dependent diabetics should make a practice of trying to keep the blood sugars from dropping too much at all times, but especially while riding (or driving), meaning it's important to do frequent blood sugar tests while on the road. And having a source of quickly-absorbed carbohydrates handy is also important (I use instant glucose tablets, carried in a travel tube), for when the symptoms of low blood sugar make themselves known. Having some hard candy to suck on also helps in preventing low blood sugar from sneaking up and doing bad things. Around 15 years ago, I managed to ride my BMW 3 miles in the wrong direction on a 4-lane, divided highway (against traffic), just following the center stripe while cars were whizzing by on both sides of me, when the blood sugar had dropped below 24 milligrams per deciliter. I lucked out while stopped at a red light when a passing pedestrian recognized "there's something wrong with this guy" and convinced me to get off the bike and walked me and the bike over to the side of the road, where a rescue ambulance showed up a few minutes later and gave me an IV of glucogon. Could have turned out much worse!