That stinks that there is only one Doctor in your area. Could you cozy up to his scheduler and maybe have her call you with a cancellation? I did that with my MS specialist's receptionist and she was a huge help. I asked if it would be ok to call her a couple of times a week to check for availability. Maybe she just got sick of hearing from me but I got in within 3 weeks as opposed the the 3 months they estimated.
The only other thing I would think is to maybe check around for another great doc and just travel to whever they are located. Wish it wasn't so difficult.