OBX-GL
What Harley suggested is what I do almost everytime I park the trailer. Additionally I take the plug out of the water heater. I was late winterizing as we had planned to use it one last time this fall. Luckily I open up everything and pulled the low water drains (just in case) before we parked it last month. I had to winterized it earlier this week after it warmed up a bit. The only thing that broke was the bypass valve on the HW bypass (t-handle broke but could turn with pliers).
Glad it worked out for you. I know winterizing is cheap insurance compared to the cost of repairing water lines and fixtures.