To have the best time possible when traveling from a low place (like Juneau) to a high place (like Denver) here are some favorite naturopathic altitude assists. There really is less oxygen at elevation. From the moment you get off the plane, start drinking a lot more liquid than you usually do. Water, water and more water (and electrolytes). Eat regularly and maintain you blood sugar. Also, be careful, alcohol has a bigger effect in high places than at sea level.
Best results come with homeopathic Coca in a 6 or 30C potency. Try taking it every few hours and/or in a water bottle spiked with the remedy. Tibetan or Machu Pichu trekkers love it. Some people swear by gingko, CoQ10, dimethylglycine and an assortment of adaptogenic mushrooms like Cordyceps and Reishi. Start early — ideally 3 to 4 weeks before travel — with your altitude adjustors. If you are the least bit anemic, try to correct that before travel. Some people are prone to swell a bit with the altitude. For them I have found a combination of Apis 30C and electrolyte replacement does the trick.
The Coca seems the best go-to remedy in my experience, although remedies like Carbo Veg and Glonoine can help if that fits your pattern. Coca hp is sometimes hard to find but is carried by Helios Pharmacy in England.