Your friend should check to make certain that the terms and conditions of the probation that the non-transferable terms and conditions of his probation have been completed before changing residence. If possible, he should complete the DUI school in California and make certain all community service hours and jail time have been done in full. I would assume that AA could be attended anywhere, but he should speak with the attorney who handled the case for him originally.
You should contact an attorney in your area to discuss the statute of limitations on a DUI case. It is possible that the prosecutor wasn't prepared to go forward with you case at your date in March, but still has an opportunity to file charges against you before the statute expires. In California, the prosecutor has one year from the date of the offense to file charges.
It is also possible, that the prosecutor has decided not to file charges. However, you mayt still be facing...
The answer to your question will be governed by the laws of your state. In California, there are different criteria for credits depending on a number of issues, such as, where you will be incarcerated and the nature of the offense.
You should contact an attorney in your area, or the attorney who represented you, to ge accurate answer to your questions.
Depending on the laws of your state, you may be able to leave the state without permission. I would review the terms and conditions of your probation as provided by the court. A call to the probation department that you will be assigned to may offer more insight. I do not practice in your state. You should consult with an attorney familiar with DUI laws in Colorado.
Depending on which state you are in, there are often ways to have your previous probation modified to allow you to have your license reinstated on a restricted basis. You will have to consult with a DUI expert in your area to provide you with accurate information about your options.
All states DMV records are interlinked via the interstate compact. You should check with the VA department of motor vehicles regarding your ability to obtain an license there. You may need to clear your California license issues prior to receiving a VA license. You can contact the California Department of Motor Vehicles Mandatory
Action Division and see if, as you no longer live in California, you can obtain a waiver of California requirements to lift any holds that my exist.