The training program in Backpacker magazine is a great reference for two months out from your Kilimanjaro trip. If you check out the article, it will explain that the body can not adapt quick enough if you wait until a month or two before attempting a challenging athletic endeavor, to start getting in shape.
For example, it takes about four months of training to be able to finish a marathon. Most people that try to run one without proper training, never make it to the finish line. This is mainly do to overuse injuries (or just not being in-shape enough) that could have been avoided by training.
5 months early is also the best time to start a basic strength training program ( which will aid in overall fitness and make it a whole lot easier without feeling like they want to crawl or pay a porter to carry them). Doing three cardio workouts a week (one longer than the others) and a couple of short and simple strength training workout – push-ups, lunges, abs, working basic large muscle groups.
Excluding the Marangu trail, 3 to 4 months prior to your climb on Mt. Kilimanjaro, you should be able hike 7 miles per day, and you should be able to do this 3 times in one week.