Complex sentence: There are two tourist resorts on the island: the original resort at the southern end caters to day visitors, only overnights guests can visit the newer resort (opened in 1990) at the north-eastern end of the island.
Split into simpler sentences: There are two tourist resorts on the island: the original resort at the southern end caters to day visitors. Only overnight guests can visit the newer resort, which was opened in 1990, at the north-eastern end of the island.