I keep my current RV plugged in all winter. It's outside with a cover on it. I run a small heater on low and it keeps the temperature inside around 40 degrees. The little electric heater eliminates any dampness.
Yours is in a garage so you probably don't have to worry about dampness.
One very important thing to note is that batteries like to be kept fully charged
. If you have a decent charging system then I would leave your RV plugged in all the time. If your charging system is basic or the voltage output is higher than 13.8 volts then I suggest not leaving it plugged in and instead buy a BatteryMINDer made by VDC Electronics and maintain the battery(ies) over winter that way.
BatteryMINDers reverse the primary cause of early battery failure known as "sulfation".
I had two BatteryMINDers for my Roadtrek. One for the engine battery and one for the house batteries.