I've been there several times. My father-in law was born there and my wife has a few relatives that we visit in Puerto Rico from time to time. Wonderful island full of a rich and diverse cultural history. I've had no problems driving on the highways in Puerto Rico, except driving in San Juan can be a nightmare sometimes, but no different than driving in any large cosmopolitan city. Definitely check out old San Juan and the El Morro fortress.
Anyway, Spanish is the language spoken by the majority, but it's easy to find English speakers. It's been part of the United States since 1898 and it's not all that different from living in the mainland.The people are also as diverse as they are here on the mainland, whites, blacks, Asians, mixed. Every one of them regard themselves as Puerto Ricans and are very friendly and lively people.