https://www.statnews.com/2020/11/11/rural-hospitals-cant-afford-freezers-to-store-pfizer-covid19-vaccine/
Ultra-cold freezers are expensive.
I found it interesting to see the CDC telling hospitals not to buy the freezers. Expensive, yes, but $10K doesn't seem like all that much compared to other medical equipment. Certainly I wouldn't expect a rural clinic to buy one, but it seems like an appropriate expense for a rural/regional hospital.
It appears at least a half dozen facilities within an hour of me have the freezers. How much vaccine they can hold to cover the region I do not know, but an hour drive, or even two or three, is not a big deal, whether it be a rural resident, or a hospital delivering vaccine to a rural clinic, where, IIRC, the vaccine can be stored for 48 hours in normal refrigeration to be handed out to elderly, etc. that can't travel.
I know Dogmush mentioned that military resources to help with distribution are being ramped up, so mobile military medical units could be a workaround for freezers in very rural areas.
Just my layman's perspective, since I know zero about distribution and logistics in the medical field.