The reason I asked about the ladder is that I once had a friend fall off a Catalina
27 while it was parked on the trailer near a boat ramp
. The ladder was simply leaning against the side and was not secured. Having a bad fall onto concrete ten miles from the nearest ambulance was not particularly fun for Bobbie. She had multiple fractures and was out of commission for a few months.
I do like your plans to make sure the trailer is well supported. If you are in a cold climate, a boom tent or similar will probably help shed snow and ice and maybe make it easier to keep the boat warm when you're working on it.