I think the best way to get into the program is through your current doctor, He/She knows your history, so you should start there. I know this can be difficult, but if you are properly informed, you can educate the doctor on how things really work.
You should start with some facts to back up why you are seeking alternative medication. Show that you have done some research, and you are not just a pothead. I know the ASA and many other organizations have pamphlets specific to different aliments. Here is a few link that might help (I am using cancer as my example)
http://www.cancer.gov/cancertopics/factsheet/Support/marijuana
http://www.gsalternative.com/2010/07/marijuana-shows-promise-as-cancer-cure/
I could list out tons of links but I think you get the point.
The most common reason I hear of that doctors give for saying they cannot sign is the risk of federal prosecution, and as their ability to write prescriptions comes from the federal government. This was the case, but it has changed. Point out they are not writing a prescription they are simply stating that, in their professional opinion, the potential benefits of medical
marijuana would likely outweigh the health risks that medical marijuana could cause..
Conant v. McCaffrey is, at its core, a case about doctors ability to give advice and recommendations to patients suffering from serious and debilitating illnesses. In October 2003, the Unites States Supreme Court let stand a ruling by the Ninth Circuit Court of Appeals permitting physicians to recommend marijuana to patients whom they believe might medically benefit from its use. Conant v. Walters, 309 F.3d 629 (2002). Thus ending the seven-year dispute between the federal government, physicians, and patients over the freedom to discuss medical marijuana as an alternative medication
I am sure this will not always work, but I hope it helps.