Regardless of your plan, you can only stay for the duration CBP allows. If an officer sees a return ticket for 2 weeks out, they could authorize your stay for only two weeks. Also what do you do if CBP sends you to secondary and they want to review your social media posts? You are not required to offer any information to CBP other than to answer their questions truthfully (purpose of visit along with who you plan to visit are fairly common questions), and you seem to have a plan on an open social media website planning to attempt a deception. As I mentioned before, not a good plan.