Folks,
You have 37 days to complete all directive stages of which you are only required to complete 5-6 individual missions per stage. Looking at the numbers in the directives, although difficult, they are doable, especially utilizing signals and camouflages. Half way through the directive stages you are rewarded the Tier VII Premium Gorizia (Upon completion of Directive 3). Everything after that is additional, helps with the PR build, or additional rewards (New Year Containers, Coal, Steel, etc).
Ultimately, Puerto Rico is an optional grind, she may not fit your play style or may not be of interest to you. Being a high value ship at Tier X, the effort needs to be worth the reward. While it will take more dedication and effort, there are means to complete the construction of PR by engaging in the game. The use of doubloons will simply allow the construction of PR expeditiously, or to assist those that may not necessarily have the time to complete all necessary directives.
No payment is mandatory to earn the USS Puerto Rico.
-Hapa