Dispersed camping at McNeil point is a backpackers dream — you get to hike far into the clouds, far away from the people, yet this location is nearly as convenient as car camping.
While McNeil point is a popular hike, most people visiting are day hikers, or backpackers taking a few days for circumnavigating the Timberline trail. Since we only had one day, we left Portland at 2 pm on a summer Friday, hiked in the four miles most of the way to McNeil, pitched the tent in time for dinner and sunset, then got up early and summited McNeil far before the summer crowds from town had time to make it to the trail head.
There are quite a few dispersed, designated spots to camp. The most obvious ones are those along the Timberline trail—and they are also likely the busiest. There are also obvious sites well up near the McNeil summit. These aren't as busy, but you'll have to haul your packs up the whole way. We chose a site that we found in a clearing that had a good view of the mountain. Note - You cannot camp in most of the meadows around the lakes. There are signs that designate this.
When we hiked up to the McNeil summit in the morning, we only took our day packs, and left our big packs in our tents. After summiting we hiked back down, cooked lunch at the campsite, and then packed out. It's definitely a recommended trip if you have a short time, but still want to feel like you got far, far away.