I basically do the same as Sgt Rock but I run RV anitifreze threw my livewell pumps and leave some in the bottom of my livewells. I have two screens setup for my livewell intakes. The one for winter which is totaly plugged with marine silicone goes on for winter. My livewell drain I use a wine bottle cork a few taps and it fits perfect. I don`t plug my overflows on the side of the boat they are high enough for me they are not an issue.
You don`t want to be missing out on some of the best fishing of the year. Get your boat ready.
Edited to add…. If you have a speedometer run by water blow the line out and plug it so you don`t bust your speedometer.