Seems foolish if this is true. Putting all your egg in one basket?
A couple of immediate reactions to this article, aside from the fact that SCMP is generally crap (not just on PLA matters) >50% of the time:
1. How much is "much"? 80%? 60%? 20%? We have no clue. The article doesn't say, so it's meaningless.
2. With regards to the "accessible by one narrow road" comment - it's pretty well-established by now that the PLARF has an "Underground Great Wall" (UGW) tunnel network in place. Does anyone HONESTLY believe that an important PLARF nuclear warhead storage facility would not be connected to UGW? By not even mentioning the UGW, this author is either playing ignorant to fulfill a quota or genuinely ignorant about Chinese nuclear deterrence.