If you want to get permission to leave the state, you want to see if your po will let you report by mail. If I were you, I would not make your desire to smoke dope the center peice of the reason why you want to move. Just sayin.
Consult with an attorney to see if you can get your probation transferred from Michigan to Colorado based upon employment opportunities NOT due to the legalization of recreational cannabis.
It might be that you can convince your PO that your job offer in Boulder is a good basis for permission to move there. As my colleagues advise, basing your request on your desire to smoke dope would not be a good strategy. Possession or use are still illegal under federal law, and it remains to be seen how the federal government will react to the legalizations.
We do not have a client/attorney relationship until you make an appointment, we discuss your case face to face, I accept a retainer, and we explictly agree to enter into representation.
If you are allowed to leave the state but continued on probation, you are still subject to staying clean from drugs. Judges can order Defendants to not do certain things that are otherwise legal. For example, probationary orders often prohibit persons over 21 years from consuming alcoholic beverages. Likewise, even a person in Michigan with a medical marijuana card can be prohibited from using marijuana.
Your best bet is to hire a lawyer to try and help you get off of probation early. Having a job in another state may be good cause to allow your probation to be terminated early - it is within the Judge's discretion. Some Defendants even seek to serve jail time rather than stay on probation. You should discuss all your options with an experienced lawyer.