Represent the collective interests of the towns.

Establish a bank, and an institution that monitors the bank.

establish economic success of the different areas and encourage trade betweens locations, with a lower tax on items within your control, and an import tax on outside influence, this way no one can quickly defraud you.

From here, respond to infrastructure issues, like mail/correspondence. Propaganda, entertainment. Roads, buildings, food.

Depending on your governing type, designate ways to communicate issues to the local authority appointed by you or elected officials, then ways it can escalate above a town level, to the three town “county” you have established, and so on.

Employ tradespeople and hauling of goods, ensure the security of the hubs/towns through means available or contracts you award to the most economical and effective bidder (this can be you, or a armed force you begin) as well as weekly protected convoys between towns for those who can wait.

The rest kind of should fall into place and respond to disasters accordingly and use the taxes you collect to fund projects from the beginning of my list, down.