Complex sentence: Connolly was built in the 1940's, Palmerton in the 1960's, and Peterson Hall in 2004 and combined can house up to 660 students on-campus.
Split into simpler sentences: Connolly was built in the 1940s, Palmerton in the 1960s, and Peterson Hall in 2004. The three combined can house up to 660 students on-campus.