As competent as these three gringo drivers seem, I managed to lure them down one way streets more than once. Some signs are clearly visible, others are non existant. Drivers should assume all streets are one way and just try to figure out which way. One time we were pulled over by very unhappy police with sirens wailing and red lights flashing. I tried to explain that (as navigator) I didn't see the one way sign, and I would be happy to pay any fine but I would really appreciate it if the drivers weren't fined because I was to blame. Once the police realised we were disoriented (well, I was) tourists, they relaxed, put their ticket pads away, got back in their cars and told us to follow them to the restaurant we were looking for. Talk about treating foreigners well, they're second to none around here!
There are a lot of seagulls around. We were having a party when we got attacked from the sky. Seagulls flying by! Actually gulls are not the only birds that fly along the coast - besides them we saw pelicans and other birds that we could not identify.
The other warning (common sense really) is watch your step in downtown Progreso. All roads are one-way streets with two lanes. Sometimes the sidewalks are barely wide enough for one person to walk, never mind two pedestrians abreast. If I wanted to walk beside my wife, I had to walk in the street, which involves a lot of checking for traffic. This only matters because Mexican drivers seemed to be a little pushy (mind you, I suspect they would not actually run you over but I didn't want to test out that theory).