Here's my take on the letter:
SUBJECT: PLEASE EXTEND THE PUBLIC COMMENT PERIOD FOR THE HAVASU TRAVEL MANAGEMENT PLAN
Dear [Letter Recipient],
It is crucial that you extend the comment period by a minimum of 60 days. A thirty day comment period is unrealistic given the amount of data and maps available.
We simply need more time to make an informed decision. Therefore, I respectfully request that you allow the comment period to be extended so that we may more fully respond.