Complex sentence: Both are in for a shock at how much the world has changed from 1956 to 1986--clothing, sexual lifestyles (their favorite bar is now a gay club), lack of respect by the younger generation, and the advance of technology.
Split into simpler sentences: Both are in for a shock at how much the world has changed from 1956 to 1986. Clothing, sexual lifestyles (they walk into their favorite bar only to find that it's now a gay club), lack of respect by the younger generation, and the advance of technology.