The first couple of times we went to Progreso (with one s) we hated it. Of course the very first time was a redirect due to a hurricane and very little had been done to make it a port of call for cruise ships. While they are working on that, it still is more like a true Mexican city rather than a resort that the cruise ship industry has built. It is just a little cleaner now and has a lot of charm.
An excursion is always nice, but if you just want to go on your own, take the bus into town and just start walking. We always enjoy the little double decker bus for a couple of bucks and a twenty minute ride to get our bearings.
The beach is nice at certain times of the year and murky at other times. There are a few restaurants across from the beach and most of them will bring you food and/or drinks across to the beach.
The streed vendors along the beach front seem more agressive to me than those in the market area. The town, the square the open air cathedral, the local supermarket that they claim to be their Wal mart and the fresh market with it's beautiful flowers and produce are all we need to enjoy a nice day strolling through town.
Oh, we also love to get beach massage before returning to the ship. We have bargained with them for a 45 min massage for $15 and it is wonderful.
We usually leave port early afternoon and just find a deck chair on the back of the ship and relax with a cold drink and a nap until sail away.
Been there - done that:
2005 Holiday, Sensation, Conquest,
2006 Conquest, Celebration, Holiday,
2007 Freedom Grand Med, Holiday
2008 Fantasy & Sensation,
2009 Fantasy, Holiday & Dream Grand Med
2010 Fantasy and B2B Elation
2011 Monarch of the Seas
2012 Booked - Breeze from Barcelona 12 days