The friendly will come three days after the U.S. take on Mexico in the Confederations Cup playoff. It falls on a FIFA date so Jurgen Klinsmann will get to call in any players he wants, but it's unclear how many of his best players will play in the contest so soon after what will assuredly be a taxing and intense match against Mexico.
It's not rare for the U.S. and Costa Rica to play friendlies. The Americans often schedule matches against CONCACAF foes and the Ticos are one of the teams that comes to the U.S. for a friendly every few years. The teams didn't cross paths at the Gold Cup so this will be their first match against each other since World Cup qualifying in 2013. With the U.S. and Costa Rica in different groups for the semifinal round of World Cup qualifying, they won't play each other again until at least November 2016, when the final round of World Cup qualifying begins.
The U.S. probably had the entire country to consider in picking a venue for this match. They could stay on the west coast and minimize travel from the Mexico match in Pasadena, CA, or they could move further east and make for shorter travel for the European contingent of players head back to their clubs after the friendly. Both would be perfectly justifiable so travel shouldn't be a huge determinant in the location of this match.