Actually, the last response is incorrect. Months in advance will make no difference; a couple of days in advance may. One should remember that it is common for those who arrive by air to be somewhat dehydrated on arrival, so drink plenty on the plane.
There are several crucial risks for the development of Acute Mountain Sickness (AMS). First and foremost is the rate of ascent, which, for skiers, arriving at a resort by plane/ car/ whatever is considerably more rapid than mountaineers who are ascending by foot. Intermediate stops are most helpful, and your stopping in Denver overnight is a good idea; even longer in Denver if AMS has been a problem for you would be better. Second is hydration status, as previously mentioned- the more dehydrated you are, the more likely you will have problems. You get more dehydrated at altitude, too, and the need for extra fluids is often underestimated. Third is the variable physiology of the individual. There are some people who are just more prone to AMS. They may do better with slower acclimization, or may just find it hard to tolerate the transition to higher altitude no matter what. They may also be helped by medications. The mountaineer's dictum of "climb high, sleep low" is a good one- stay at a hotel at a lower altitude if possible. Even 500 ft may make a difference for some, but remember, the lifts speed your ascent, too- you can gain 2500 or more vertical feet in 10 minutes, as opposed to the climber's 1000 vertical feet per hour under good conditions.
Sleep disturbance is very common for flatlanders staying above 7000 ft, and is at least in part related to disordered breathing from altitude. Headaches can be just simple AMS (more likely at CO altitudes) but can be an early sign of HACE- high altitude cerebral edema (swelling of the brain). This is generally not a problem below 10,000 feet, but can be, and is serious business, requiring rapid descent. If it is relieved by aspirin and fluids, it is usually not HACE.
The most commonly used medication for speeding acclimization is acetazolamide (Diamox). Without going into the pharmacology and physiology, suffice it to say that it accelerates some of the physiologic mechanisms that your body used to adapt to altitude. It is not without side effects, however, so I would not recommend it unless you have had problems in the past. Side effects include increased urination (actually this is something that happens at altitude to everyone- another reason you need to drink alot) and tingling of the hands and feet. People who are allergic to sulfa drugs usually have allergy to Diamox as well- it is a sulfonamide derivative. Recent data suggest that as little as 125 mg twice a day is often effective (with fewer side effects than larger doses).
Mild AMS can generally be managed with fluids and aspirin, but if you are really sick (especially if there is any sign of HACE or HAPE (edema of the lungs) you should descend- it is the first and best treatment. Even 1000 ft often makes an enourmous difference. Other treatments (oxygen, albuterol and other beta agonists, steroids such as dexamethasone) are probably more than you want to deal with when you can easily get in a car and drop down below 7500 ft.
About ginko balboa- some of my colleagues here at the U of CO Medical School and the CO Center for Altitude Medicine and Physiology are doing a controlled study of it for prevention of AMS. I, of course, was stuck in the OR and missed the seminar where they presented their preliminary results! There are a couple of promising early studies, but no definitive data yet as far as I know. I believe that you do need to start it at least a week in advance of your ascent, however.
Here's a good website with lots of information: http://www.high-altitude-medicine.com/