Brief Answer:
There isn't great ways.

Detailed Answer:
There are several stages of crystal meth withdrawal. Acutely there is increased sleep to get back sleep deficit (get back the sleep you didn't get during the use). This lasts about 2-3 days with ONE use. With daily use for a week or more then it will last more than 2-3 days, but certainly not 2 weeks. It varies. But generally 5 to 7 days.
The next phases get quite tricky. There is the subacute stage of getting thinking back to a more normal order. And there is the long term phase of the brain going back to a normal structure and function. The latest research is that there IS a long term phase, when 10 years ago we thought the brain changes associated with crystal meth were like a permanent brain damage. More of a question is how someone can be at work in the middle of a crystal meth 9 week binge. Certainly this would not be expected to look like one's normal self nor how one will look after a binge.

Then, one can make an estimate of practically anything just by connecting observations together and making a curve. If someone is close to normal by day 3, then they will be more normal by day 5 and they are unlikely to backtrack. If recovery is fast, then it will stay fast.

On how to speed recovery: first the drug is out of the system entirely by hours. There isn't anyway (or need) to speed that up. Then there is the acute need for sleep. While stiimulants overcome this, they shouldn't be used. and instead, someone should just increase sleep. Then there is the brain recovery. Normal patterns of eating and sleeping would be helpful for this.

Larger issues are staying off of further drugs. The feelings of withdrawal are quite a triggger to go back to stimulant abuse. For that matter use of stimulants are a trigger also (including caffeine and energy drinks). These should all be avoided. and 12 step programs, counseling, and more stable environment. Avoiding people and situations connected to using drugs should be avoided.

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