Unlike many of the other 8,000-meter peaks, K2 is so remote that it is not visible from any inhabited place. The nearest village on the south (Pakistan) side of the mountain is Askole, approximately 6-8 days from Base Camp. The nearest town with medical supplies and a phone is another 8-10 hours (via jeeps which must be prescheduled), so it is advisable to consider bringing a satellite telephone. The Pakistan side of the mountain is the more frequently visited side, but you can still expect a limited number of climbers – in a "low" season there will be as few as 20, and a "peak" season will see only approximately 40-50. This is due primarily to the difficulty of the mountain. The trek to BC takes around 8 days and there are no tea houses on the way. You camp out in tents and own cooking is required. The gear is carried by porters, those - as opposite to Everest sherpas - preferring drums to North Face bags or other soft packs. The porters allow 55 lbs each, charging USD 8/day or USD 64/load coming in and out (plus tips 10-20%).
Approaching K2 from the Chinese side is a huge logistical challenge. From Kashgar, in the "wild west" Xinjiang province of China, there is a 2 day bus ride, followed by a 2 day off-road jeep ride through the Tashkurgan Desert (which, literally translated, means "If you go in, you will not come back") to an oasis called "Ilik" where you rendezvous with the camels who will transport your gear to Base Camp. The 8-day trek with the camels takes you through the prehistoric canyons of the Shaksgam Valley, across rivers which are frequently so deep that you have to ride the camels, to the base of the Qogori (K2) Glacier.
At the base of the glacier, the camels can go no further, but you are still 2,000 feet below and 10 miles away from the base of the mountain. At this point your 3 months of food and climbing gear (often weighing as much as 15,000 pounds) must be extremely well organized so that you know which loads to carry up first. After a week or so of carrying heavy loads on loose scree for 10-12 hours per day, you may have enough gear to start climbing. Many expeditions choose to hire porters from Pakistan to help with ongoing task of carrying equipment from the camel dump to the base of the mountain throughout the season.
As if this month-long approach weren’t challenge enough, there is the added element of seasonal flooding in the Shaksgam Valley. Once the rivers flood in late June, even the camels cannot cross them. It is effectively impossible to trek back out, and helicopter rescue or supply drops are not an option. (Chinese airstrips are too far away, and Pakistani helicopters cannot enter Chinese air space.) Your team will be completely isolated until the rivers recede in early to mid-August.
The Chinese side of the mountain is the less frequently visited side, and there are usually no climbers on this side of the mountain. Historically, teams on this side of the team have either been very large, or loose-knit groups of smaller international teams working together.
Buy small padlocks for everything. The luggage will be left unattended at times on its way to BC. Pack everything bearing in mind that it will be carried. Tubes with ketchup will get pierced, jam jars will leak, sugar will end up in your underwear change. Keep everything well packed and isolated in plastic bunks if you don’t want to forever remember the climb by the smell of various food products. Potato chips should be Pringles, if not for the taste then for the hard pack. Remember that all the foods and technical gear must withstand extreme temperatures, both hot and cold.