We always park with the Port of Galveston, and when cruising with
DCL, park in the SMP garage. There is an uncovered lot adjacent to terminal #28 (only terminal we've sailed out of with DCL), but we prefer to be in covered. I understand that nothing is guaranteed, but they advertise that the port of Galveston police patrol their parking lots 24/7, which I'm not sure if the other lots are monitored. You can prebook (we always do upon booking the cruise, since the garage tends to go first) and right now, they're doing $5 off with promo code: TRICKORTREAT24
My son and I went on the Magic from Galveston last January, and it ended up being canceled/a day at sea due to high winds. I've read that Progreso tends to be canceled frequently, so I was prepared for it. We were able to dock during our Thanksgiving 2022 cruise, but sailing out of Galveston we were rolling quite a bit due to rough seas. I thought it was pretty cold during January, but kids were still swimming and going back and forth from the pool to the hot tub, and I used the blankets DCL provides while lounging by the Funnel Vision. I believe it rained one day at sea and pretty much overcast the of the days.
I don't think Progreso is really considered a "beach" port. We did the DCL port adventure PGO24, and I didn't think the beach was anything spectacular, but the service was wonderful.
I understand that the port adventures to Chichen Itza are very long days, but since we booked through DCL, we were confident of not missing the ship versus booking independently. We rarely do land vacations, so to be able to visit one of the Seven Wonders of the World would've been amazing. There are other smaller and closer Mayan Ruins and cenotes that you can visit that, but I believe the Mayapan Ruins are still closed due to protests by the locals not receiving fair compensation. We were going back and forth between Mayapan and Chichen Itza due to the distance, but once I read about the protests, we obviously chose the latter. At that time, they were canceling the Mayapan port adventures while on the sailing, so I didn't want to get stuck with nothing else to book. My son was bummed that we couldn't visit Chichen Itza, so hopefully we'll be able to visit in the near future.
Hope you have a great sailing!