How to shorten Puerto Rico to fit one hour?
We have played 2-3 times a month for a long time.

Of course games are shorter with fewer people and go faster when everyone is well acquainted with the game.  We have played normal extended version games in about an hour with 3 people.

We recently added a column of property spaces on each town to extend play - you could remove a column to shorten play.

You can deal out some random plantations at the start to accelerate play (like a bunch of Hacienda plays.)  You may give everyone a quarry to accelerate play.  You may add squares to the trading center or to the ships to accelerate play. You may add 2 coins jnstead of one to unused roles. Note that any of these steps will alter the playing strategies from a normal game.

Cheers.