I will make the pitch for Hawaii. (And I have traveled extensively in Mexico and latin america.)

You don't have to worry about crime (a serious concern these days in Mexico). You don't have to worry about what you eat or drink. There are no peddlers on the beach. The ocean is nicer (cleaner, clearer) than PV. The pace of life is relaxed and easy, but sanitation is first world and everything works.

I'm particularly a fan of the north shores of Oahu and Kauai. But even Waikiki is fun for a couple of days.

As far as getting there, OP, I would advise first of all you pick a widebody flight out of IAH, LAX, SFO, or DEN. The 764 out of SFO has the best front cabin. 160,000 miles will get you two saver F awards. It may take some looking to find availability on your desired routes.

Alternatively, you could buy economy tickets and upgrade with miles. To upgrade a cheap economy ticket will cost (probably) 55,000 miles and $250 per RT ticket. UA makes a fair bit of upgrade space available on the Hawaii routes. You want to find flights with "R" space so that you can confirm the upgrade at booking.